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472k
1998-05-11T05:39:17
9708
alg-geom/9708002
en
https://arxiv.org/abs/alg-geom/9708002
[ "alg-geom", "math.AG" ]
alg-geom/9708002
James A. Carlson
James A. Carlson and Domingo Toledo
Discriminant Complements and Kernels of Monodromy Representations
20 page dvi file available at http://www.math.utah.edu/~carlson/eprints.html Minor changes for final version to appear in Duke J. Math
null
null
null
null
We show that the kernel of the monodromy representation for hypersurfaces of degree d and dimension n is large for d at least three with the exception of the cases (d,n) = (3,0) and (3,1). For these the kernel is finite. By "large" we mean a group that admits a homomorphism to a semisimple Lie group of noncompact typ...
[ { "version": "v1", "created": "Fri, 1 Aug 1997 23:18:27 GMT" }, { "version": "v2", "created": "Fri, 13 Feb 1998 16:48:02 GMT" }, { "version": "v3", "created": "Mon, 11 May 1998 03:39:15 GMT" } ]
2008-02-03T00:00:00
[ [ "Carlson", "James A.", "" ], [ "Toledo", "Domingo", "" ] ]
alg-geom
\section{Introduction} \secref{introsection} A hypersurface of degree $d$ in a complex projective space $\P^{n+1}$ is defined by an equation of the form $$ F(x) = \sum a_L x^L = 0, \eqn \eqref{universalhypersurface} $$ where $x^L = x_0^{L_0} \cdots x_{n+1}^{L_{n+1}}$ is a monomial of degree $d$ and where t...
1997-08-14T10:59:42
9708
alg-geom/9708012
en
https://arxiv.org/abs/alg-geom/9708012
[ "alg-geom", "math.AG" ]
alg-geom/9708012
Lothar Goettsche
Barbara Fantechi, Lothar G\"ottsche, Duco van Straten
Euler number of the compactified Jacobian and multiplicity of rational curves
LaTeX, 16 pages with 1 figure
null
null
null
null
We show that the Euler number of the compactified Jacobian of a rational curve $C$ with locally planar singularities is equal to the multiplicity of the $\delta$-constant stratum in the base of a semi-universal deformation of $C$. In particular, the multiplicity assigned by Yau, Zaslow and Beauville to a rational cur...
[ { "version": "v1", "created": "Thu, 14 Aug 1997 08:59:50 GMT" } ]
2008-02-03T00:00:00
[ [ "Fantechi", "Barbara", "" ], [ "Göttsche", "Lothar", "" ], [ "van Straten", "Duco", "" ] ]
alg-geom
\section{Introduction} Let $C$ be a reduced and irreducible projective curve with singular set $\Sigma \subset C$ and let $n: \widetilde{C} \longrightarrow C$ be its normalisation. The generalised Jacobian $JC$ of $C$ is an extension of $J\widetilde{C}$ by an affine commutative group of dimension $$\delta:=\dim H^0(n_...
1997-12-16T01:08:53
9708
alg-geom/9708007
en
https://arxiv.org/abs/alg-geom/9708007
[ "alg-geom", "math.AG" ]
alg-geom/9708007
Yuri G. Zarhin
Yuri G. Zarhin
Torsion of abelian varieties, Weil classes and cyclotomic extensions
LaTeX 2e 17 pages
null
null
null
null
Let $K$ be a field finitely generated over the field of rational numbers, $K(c)$ the extension of $K$ obtained by adjoining all roots of unity, $L$ an infinite Galois extension of $K$, $X$ an abelian variety defined over $K$. We prove that under certain conditions on $X$ and $K$ the existence of infinitely many L-rat...
[ { "version": "v1", "created": "Mon, 4 Aug 1997 23:46:42 GMT" }, { "version": "v2", "created": "Wed, 27 Aug 1997 19:17:28 GMT" }, { "version": "v3", "created": "Wed, 3 Sep 1997 15:12:11 GMT" }, { "version": "v4", "created": "Tue, 9 Sep 1997 16:53:41 GMT" }, { "vers...
2008-02-03T00:00:00
[ [ "Zarhin", "Yuri G.", "" ] ]
alg-geom
\section{Main construction} Let $F$ be the center of $\mathrm{End}_K(X)\otimes{\mathbf Q}$, $R_F=F\bigcap \mathrm{End}_K(X)$ the center of $\mathrm{End}_K(X)$. We put $$V_{{\mathbf Z}}=V_{{\mathbf Z}}(X)=H_1(X({\mathbf C}),{\mathbf Z}), \quad V=V(X)=H_1(X({\mathbf C}),{\mathbf Q})= V_{{\mathbf Z}}\otimes{\mathbf Q}....
1997-08-22T16:19:27
9708
alg-geom/9708020
en
https://arxiv.org/abs/alg-geom/9708020
[ "alg-geom", "math.AC", "math.AG" ]
alg-geom/9708020
Gunnar Floystad
Gunnar Floystad
A property deducible from the generic initial ideal
Completely revised compared to earlier hardcopy versions. AMS-Latex v1.2, 13 pages
Journal of Pure and Applied Algebra, 136 (1999), no.2, p.127-140
10.1016/S0022-4049(97)00165-5
null
null
Let $S_d$ be the vector space of monomials of degree $d$ in the variables $x_1, ..., x_s$. For a subspace $V \sus S_d$ which is in general coordinates, consider the subspace $\gin V \sus S_d$ generated by initial monomials of polynomials in $V$ for the revlex order. We address the question of what properties of $V$ m...
[ { "version": "v1", "created": "Fri, 22 Aug 1997 14:19:15 GMT" } ]
2011-12-14T00:00:00
[ [ "Floystad", "Gunnar", "" ] ]
alg-geom
\section*{Introduction} During the recent years the generic initial ideal of a homogeneous ideal has attracted some attention as an invariant. An intriguing problem is what algebraic or geometric properties of the original ideal can be deduced from the generic initial ideal. In this paper we take perhaps the most el...
1997-08-22T10:49:15
9708
alg-geom/9708019
en
https://arxiv.org/abs/alg-geom/9708019
[ "alg-geom", "math.AG" ]
alg-geom/9708019
Alexander A. Voronov
Alexander A. Voronov (RIMS and M.I.T.)
Stability of the Rational Homotopy Type of Moduli Spaces
7 pages, 1 figure
null
null
RIMS-1157
null
We show that for g > 2k+2 the k-rational homotopy type of the moduli space M_{g,n} of algebraic curves of genus g with n punctures is independent of g, and the space M_{g,n} is k-formal. This implies the existence of a limiting rational homotopy type of M_{g,n} as g goes to infinity and the formality of it.
[ { "version": "v1", "created": "Fri, 22 Aug 1997 08:49:13 GMT" } ]
2008-02-03T00:00:00
[ [ "Voronov", "Alexander A.", "", "RIMS and M.I.T." ] ]
alg-geom
\section*{Introduction} The description of the algebraic topology of the moduli space $\mgn{g}$ of compact complex algebraic curves has long been a tantalizing problem. The idea of ``stable cohomology '' of $\mgn{g}$ as the genus $g \to \infty$, brought in by J.~L. Harer and D.~Mumford, suggested a more graspable obj...
1997-08-07T16:22:05
9708
alg-geom/9708010
en
https://arxiv.org/abs/alg-geom/9708010
[ "alg-geom", "math.AG", "math.QA", "q-alg" ]
alg-geom/9708010
Carlos Simpson
Carlos Simpson (CNRS, Universit\'e Paul Sabatier, Toulouse, France)
Limits in $n$-categories
Approximately 90 pages
null
null
null
null
We define notions of direct and inverse limits in an $n$-category. We prove that the $n+1$-category $nCAT'$ of fibrant $n$-categories admits direct and inverse limits. At the end we speculate (without proofs) on some applications of the notion of limit, including homotopy fiber product and homotopy coproduct for $n$-...
[ { "version": "v1", "created": "Thu, 7 Aug 1997 16:31:55 GMT" } ]
2008-02-03T00:00:00
[ [ "Simpson", "Carlos", "", "CNRS, Université Paul Sabatier, Toulouse, France" ] ]
alg-geom
\section*{Limits in $n$-categories} Carlos Simpson\newline CNRS, UMR 5580, Universit\'e Paul Sabatier, 31062 Toulouse CEDEX, France. \bigskip \numero{Introduction} One of the main notions in category theory is the notion of limit. Similarly, one of the most commonly used techniques in homotopy theory is the notion...
1997-08-18T09:52:59
9708
alg-geom/9708014
en
https://arxiv.org/abs/alg-geom/9708014
[ "alg-geom", "math.AG" ]
alg-geom/9708014
Leticia B. Paz
L. Brambila-Paz and H. Lange
A stratification of the moduli space of vector bundles on curves
Latex, Permanent e-mail L. Brambila-Paz: lebp@xanum.uam.mx Classification: 14D, 14F
null
null
null
null
Let $E$ be a vector bundle of rank $r\geq 2$ on a smooth projective curve $C$ of genus $g \geq 2$ over an algebraically closed field $K$ of arbitrary characteristic. For any integer with $1\le k\le r-1$ we define $${\se}_k(E):=k\deg E-r\max\deg F.$$ where the maximum is taken over all subbundles $F$ of rank $k$ of $E...
[ { "version": "v1", "created": "Mon, 18 Aug 1997 07:52:26 GMT" } ]
2016-08-30T00:00:00
[ [ "Brambila-Paz", "L.", "" ], [ "Lange", "H.", "" ] ]
alg-geom
\section{The invariants ${ {}{\mbox{\euf s}_k}}(E)$} Let $C$ be a smooth projective curve of genus $g\ge 2$ over an algebraically closed field $K$ of arbitrary characteristic. and let $E$ denote a vector bundle of rank $r\ge 2$ over $C$. For any integer $k$ with $1\le k\le r-1$ let ${}{Sb_k}(E)$ denote the {\it set ...
1998-08-05T18:28:10
9708
alg-geom/9708011
en
https://arxiv.org/abs/alg-geom/9708011
[ "alg-geom", "math.AG" ]
alg-geom/9708011
Balazs Szendroi
Balazs Szendroi
Some finiteness results for Calabi-Yau threefolds
15 pages LaTex, uses amstex, amscd. New title, paper completely rewritten, results same as in previous versions
null
null
null
null
We investigate the moduli theory of Calabi--Yau threefolds, and using Griffiths' work on the period map, we derive some finiteness results. In particular, we confirm a prediction of Morrison's Cone Conjecture.
[ { "version": "v1", "created": "Tue, 12 Aug 1997 15:15:06 GMT" }, { "version": "v2", "created": "Wed, 29 Oct 1997 11:38:37 GMT" }, { "version": "v3", "created": "Wed, 5 Aug 1998 16:28:09 GMT" } ]
2008-02-03T00:00:00
[ [ "Szendroi", "Balazs", "" ] ]
alg-geom
\section*{Introduction} If $X$ is a smooth complex projective $n$-fold, Hodge--Lefschetz theory provides a filtration on the primitive cohomology $H^n_0(X,{\mathbb C})$ by complex subspaces, satisfying certain compatibility conditions with a bilinear form $Q$ on cohomology. This gives a map called the {\it period ma...
1997-08-26T19:03:35
9708
alg-geom/9708022
en
https://arxiv.org/abs/alg-geom/9708022
[ "alg-geom", "math.AC", "math.AG" ]
alg-geom/9708022
Uwe Nagel
J. C. Migliore, U. Nagel, C. Peterson
Buchsbaum-Rim sheaves and their multiple sections
27 pages, AMS-LaTeX
null
null
null
null
This paper begins by introducing and characterizing Buchsbaum-Rim sheaves on $Z = \Proj R$ where $R$ is a graded Gorenstein K-algebra. They are reflexive sheaves arising as the sheafification of kernels of sufficiently general maps between free R-modules. Then we study multiple sections of a Buchsbaum-Rim sheaf $\cBf...
[ { "version": "v1", "created": "Tue, 26 Aug 1997 17:03:21 GMT" } ]
2008-02-03T00:00:00
[ [ "Migliore", "J. C.", "" ], [ "Nagel", "U.", "" ], [ "Peterson", "C.", "" ] ]
alg-geom
\section{Introduction} A fundamental method for constructing algebraic varieties is to consider the degeneracy locus of a morphism between a pair of coherent sheaves. By varying the morphism one obtains families of varieties. By placing various restrictions on the coherent sheaves one can force the degeneracy locus to...
2005-11-19T08:38:21
9708
alg-geom/9708006
en
https://arxiv.org/abs/alg-geom/9708006
[ "alg-geom", "math.AC", "math.AG" ]
alg-geom/9708006
Joseph Lipman
Leovigildo Alonso, Ana Jeremias, Joseph Lipman
Duality and flat base change on formal schemes
89 pages. Change from published version: in section 2.5, about dualizing complexes on formal schemes, a weakening of one flawed Lemma is proved, and shown adequate for the several applications made of the original. For another correction, see math.AG/0106239
Contemporary Math. 244 (1999), 3-90
null
null
null
We give several related versions of global Grothendieck Duality for unbounded complexes on noetherian formal schemes. The proofs, based on a non-trivial adaptation of Deligne's method for the special case of ordinary schemes, are reasonably self-contained, modulo the Special Adjoint Functor Theorem. An alternative ap...
[ { "version": "v1", "created": "Mon, 4 Aug 1997 17:48:14 GMT" }, { "version": "v2", "created": "Wed, 14 Oct 1998 18:40:15 GMT" }, { "version": "v3", "created": "Sat, 19 Nov 2005 07:38:21 GMT" } ]
2008-02-03T00:00:00
[ [ "Alonso", "Leovigildo", "" ], [ "Jeremias", "Ana", "" ], [ "Lipman", "Joseph", "" ] ]
alg-geom
\section{Preliminaries and main theorems.} \label{S:prelim} First we need some notation and terminology. Let $X$ be a ringed space,\index{ringed space} i.e., a topological space together with a sheaf of commutative rings ${\mathcal O}_{\<\<X}$.% \index{ ${\mathbf R}$@${\mathcal O}_{\<\<\<X}$ (structure sheaf of ringe...
1998-01-30T16:29:59
9708
alg-geom/9708016
en
https://arxiv.org/abs/alg-geom/9708016
[ "alg-geom", "math.AG" ]
alg-geom/9708016
Nhadhule
Klaus Hulek
Nef Divisors on Moduli Spaces of Abelian Varieties
LaTeX2e, 23 pages. The proof of the main result has been shortened. In particular, the former technical propositions 4.3 and 4.4 were replaced by a simpler argument
null
null
null
null
We determine the cone of nef divisors on the Voronoi compactification A_g^* of the moduli space A_g of principally polarized abelian varieties of dimension g for genus g=2,3. As a corollary we obtain that the spaces A_g^*(n) with level-n structure are a minimal, resp. canonical, model for g=2, n>=4, resp. n>=5 and g=...
[ { "version": "v1", "created": "Tue, 19 Aug 1997 12:24:04 GMT" }, { "version": "v2", "created": "Fri, 30 Jan 1998 15:29:58 GMT" } ]
2008-02-03T00:00:00
[ [ "Hulek", "Klaus", "" ] ]
alg-geom
\section{Introduction} Let ${\cal A}_g$ be the moduli space of principally polarized abelian varieties of dimension $g$. Over the complex numbers ${\cal A}_g={\mathbb{H}}_g/\Gamma_g$ where ${\mathbb{H}}_g$ is the Siegel space of genus $g$ and $\Gamma_g=\on{Sp}(2g,{\mathbb{Z}})$. We denote the torodial compactification...
1997-08-26T18:18:51
9708
alg-geom/9708021
en
https://arxiv.org/abs/alg-geom/9708021
[ "alg-geom", "math.AC", "math.AG" ]
alg-geom/9708021
Uwe Nagel
M. Kreuzer, J. C. Migliore, U. Nagel, C. Peterson
Determinantal schemes and Buchsbaum-Rim sheaves
20 pages, LaTeX
null
null
null
null
Let $\phi$ be a generically surjective morphism between direct sums of line bundles on $\proj{n}$ and assume that the degeneracy locus, $X$, of $\phi$ has the expected codimension. We call $B_{\phi} = \ker \phi$ a (first) Buchsbaum-Rim sheaf and we call $X$ a standard determinantal scheme. Viewing $\phi$ as a matrix ...
[ { "version": "v1", "created": "Tue, 26 Aug 1997 16:18:20 GMT" } ]
2008-02-03T00:00:00
[ [ "Kreuzer", "M.", "" ], [ "Migliore", "J. C.", "" ], [ "Nagel", "U.", "" ], [ "Peterson", "C.", "" ] ]
alg-geom
\section{Introduction} A natural and efficient method for producing numerous examples of interesting schemes is to consider the vanishing locus of the minors of a homogeneous polynomial matrix. If the matrix satisfies certain genericity conditions then the resulting schemes have a number of well described properties. ...
1997-08-29T22:11:12
9708
alg-geom/9708026
en
https://arxiv.org/abs/alg-geom/9708026
[ "alg-geom", "math.AG" ]
alg-geom/9708026
Frank Sottile
Frank Sottile (University of Toronto)
Pieri-type formulas for maximal isotropic Grassmannians via triple intersections
LaTeX 2e, 24 pages (9 pages is an appendix detailing the proof in the symplectic case). Expanded version of MSRI preprint 1997-062
Colloquium Mathematicum, Vol. 82 (1999), 49--63.
null
null
null
We give an elementary proof of the Pieri-type formula in the cohomology of a Grassmannian of maximal isotropic subspaces of an odd orthogonal or symplectic vector space. This proof proceeds by explicitly computing a triple intersection of Schubert varieties. The decisive step is an explicit description of the interse...
[ { "version": "v1", "created": "Fri, 29 Aug 1997 20:10:43 GMT" } ]
2008-02-03T00:00:00
[ [ "Sottile", "Frank", "", "University of Toronto" ] ]
alg-geom
\section*{Introduction} The goal of this paper is to give an elementary geometric proof of Pieri-type formulas in the cohomology of Grassmannians of maximal isotropic subspaces of odd orthogonal or symplectic vector spaces. For this, we explicitly compute a triple intersection of Schubert varieties, where one is a spe...
1998-11-25T06:12:16
9708
alg-geom/9708004
en
https://arxiv.org/abs/alg-geom/9708004
[ "alg-geom", "math.AG" ]
alg-geom/9708004
Mark De Cataldo
Mark Andrea A. de Cataldo
Effective nonvanishing, effective global generation
LaTex (article) 13 pages; revised: one section added; to appear in Ann. Inst. Fourier
null
null
null
null
We prove a multiple-points higher-jets nonvanishing theorem by the use of local Seshadri constants. Applications are given to effectivity problems such as constructing rational and birational maps into Grassmannians, and the global generation of vector bundles.
[ { "version": "v1", "created": "Sat, 2 Aug 1997 01:50:03 GMT" }, { "version": "v2", "created": "Wed, 25 Nov 1998 05:12:29 GMT" } ]
2008-02-03T00:00:00
[ [ "de Cataldo", "Mark Andrea A.", "" ] ]
alg-geom
\section{Introduction} \label{intr} Koll\'ar's nonvanishing theorem \ci{koebpf}, 3.2 is an instrument to make Kawamata-Shokurov base-point-freeness assertion into an effective one. His result can be applied to a variety of other situations; see \ci{koebpf}, \S4, \ci{koshafinv}, \S8 and \ci{koshaf}, \S14. The basic ...
1997-08-29T11:25:45
9708
alg-geom/9708025
en
https://arxiv.org/abs/alg-geom/9708025
[ "alg-geom", "math.AG" ]
alg-geom/9708025
Georg Hein
Georg Hein
Duality Construction of Moduli Spaces
12 pages LaTeX using pb-diagram.sty
null
null
null
null
We show for the moduli space of rank-2 coherent sheaves on an algebraic surface that there exists a 'dual' moduli space. This dual space allows a construction of the first one without using the GIT construction. Furthermore, we obtain a Barth-morphism, generalizing the concept of jumping lines. This morphism is by co...
[ { "version": "v1", "created": "Fri, 29 Aug 1997 09:25:28 GMT" } ]
2008-02-03T00:00:00
[ [ "Hein", "Georg", "" ] ]
alg-geom
\section*{Introduction} In \S 1 of Faltings' article \cite{Fal} a ``GIT-free'' construction is given for the moduli spaces of vector bundles on curves using generalized theta functions. Incidentally, this construction is implicitly described in Le Potier's article \cite{LP2}. The aim of this paper is to generalize the ...
1998-11-25T06:04:39
9708
alg-geom/9708003
en
https://arxiv.org/abs/alg-geom/9708003
[ "alg-geom", "math.AG" ]
alg-geom/9708003
Mark De Cataldo
Mark Andrea A. de Cataldo
Singular hermitian metrics on vector bundles
LaTex (article) 25 pages; revised: minor changes; to appear in Crelle's J; dedicated to Michael Schneider
null
null
null
null
We introduce a notion of singular hermitian metrics (s.h.m.) for holomorphic vector bundles and define positivity in view of $L^2$-estimates. Associated with a suitably positive s.h.m. there is a (coherent) sheaf 0-th kernel of a certain $d''$-complex. We prove a vanishing theorem for the cohomology of this sheaf. Al...
[ { "version": "v1", "created": "Sat, 2 Aug 1997 01:32:14 GMT" }, { "version": "v2", "created": "Wed, 25 Nov 1998 05:05:36 GMT" } ]
2008-02-03T00:00:00
[ [ "de Cataldo", "Mark Andrea A.", "" ] ]
alg-geom
\section{Introduction} In this study I introduce a notion of singular hermitian metrics ({\em s.h.m.}) on holomorphic vector bundles over complex manifolds. The original motivation was to explore the possibility of employing, in the setting of vector bundles, the new transcendental techniques developed by Demailly and...
1997-09-04T21:02:01
9708
alg-geom/9708001
en
https://arxiv.org/abs/alg-geom/9708001
[ "alg-geom", "math.AG" ]
alg-geom/9708001
Rahul Pandharipande
T. Graber and R. Pandharipande
Localization of virtual classes
29 pages, LaTeX2e, General revision including error corrections
null
null
null
null
We prove a localization formula for virtual fundamental classes in the context of torus equivariant perfect obstruction theories. As an application, the higher genus Gromov-Witten invariants of projective space are expressed as graph sums of tautological integrals over moduli spaces of stable pointed curves (generali...
[ { "version": "v1", "created": "Fri, 1 Aug 1997 21:03:40 GMT" }, { "version": "v2", "created": "Thu, 4 Sep 1997 19:01:26 GMT" } ]
2008-02-03T00:00:00
[ [ "Graber", "T.", "" ], [ "Pandharipande", "R.", "" ] ]
alg-geom
\section{\bf{Introduction}} We prove a localization formula for the virtual fundamental class in the general context of $\mathbb{C}^*$-equivariant perfect obstruction theories. Let $X$ be an algebraic scheme with a $\mathbb{C}^*$-action and a $\mathbb{C}^*$-equivariant perfect obstruction theory. The virtual fundament...
1998-04-03T02:11:23
9702
alg-geom/9702015
en
https://arxiv.org/abs/alg-geom/9702015
[ "alg-geom", "math.AG" ]
alg-geom/9702015
Rick Miranda
C. Ciliberto (U. of Rome II), R. Miranda (Colorado State U.)
Degenerations of Planar Linear Systems
material is streamlined and some is moved to a forthcoming paper
null
null
null
null
Fixing $n$ general points $p_i$ in the plane, what is the dimension of the space of plane curves of degree $d$ having multiplicity $m_i$ at $p_i$ for each $i$? In this article we propose an approach to attack this problem, and demonstrate it by successfully computing this dimension for all $n$ and for $m_i$ constant,...
[ { "version": "v1", "created": "Fri, 21 Feb 1997 20:37:02 GMT" }, { "version": "v2", "created": "Fri, 3 Apr 1998 00:11:22 GMT" } ]
2008-02-03T00:00:00
[ [ "Ciliberto", "C.", "", "U. of Rome II" ], [ "Miranda", "R.", "", "Colorado State U." ] ]
alg-geom
\section*{Introduction} Fix the projective plane ${\mathbb{P}}^2$ and $n+1$ general points $p_0, p_1, \ldots, p_n$ in it. Let $H$ denote the line class of the plane. Consider the linear system consisting of plane curves of degree $d$ (that is, divisors in $|dH|$) with multiplicity $m_0$ at $p_0$ and multiplicity $m_i$ ...
1997-02-20T16:46:35
9702
alg-geom/9702013
en
https://arxiv.org/abs/alg-geom/9702013
[ "alg-geom", "math.AG" ]
alg-geom/9702013
Gian Mario Besana
Alberto Alzati, Marina Bertolini, Gian Mario Besana
Numerical Criteria for vey Ampleness of Divisors on Projective Bundles over an elliptic curve
AMS-Latex, 18 pages, Canadian Journal of Math, Dec 1996
null
null
null
null
In Butler, J.Differential Geom. 39 (1):1--34,1994, the author gives a sufficient condition for a line bundle associated with a divisor D to be normally generated on $X=P(E)$ where E is a vector bundle over a smooth curve C. A line bundle which is ample and normally generated is automatically very ample. Therefore the...
[ { "version": "v1", "created": "Thu, 20 Feb 1997 15:48:41 GMT" } ]
2019-08-17T00:00:00
[ [ "Alzati", "Alberto", "" ], [ "Bertolini", "Marina", "" ], [ "Besana", "Gian Mario", "" ] ]
alg-geom
\section{Introduction} Ampleness of divisors on algebraic varieties is a numerical property. On the other hand it is in general very difficult to give numerical necessary and sufficient conditions for the very ampleness of divisors. In \cite{bu} the author gives a sufficient condition for a line bundle associated with...
1997-02-14T20:33:23
9702
alg-geom/9702010
en
https://arxiv.org/abs/alg-geom/9702010
[ "alg-geom", "math.AG" ]
alg-geom/9702010
Michael Finkelberg
Michael Finkelberg and Alexander Kuznetsov (Independent University of Moscow)
Global Intersection Cohomology of Quasimaps' Spaces
21 pages, AmsLatex 1.1
null
null
null
null
Let $C$ be a smooth projective curve of genus 0. Let $\CB$ be the variety of complete flags in an $n$-dimensional vector space $V$. Given an $(n-1)$-tuple $\alpha\in\BN[I]$ of positive integers one can consider the space $\CQ_\alpha$ of algebraic maps of degree $\alpha$ from $C$ to $\CB$. This space admits some remar...
[ { "version": "v1", "created": "Fri, 14 Feb 1997 18:22:28 GMT" } ]
2016-08-30T00:00:00
[ [ "Finkelberg", "Michael", "", "Independent University of\n Moscow" ], [ "Kuznetsov", "Alexander", "", "Independent University of\n Moscow" ] ]
alg-geom
\section{Introduction} \subsection{} Let $C$ be a smooth projective curve of genus 0. Let $\CB$ be the variety of complete flags in an $n$-dimensional vector space $V$. Given an $(n-1)$-tuple $\alpha\in\BN[I]$ of positive integers one can consider the space $\CQ_\alpha$ of algebraic maps of degree $\alpha$ from $C$ to...
1997-02-28T16:42:10
9702
alg-geom/9702016
en
https://arxiv.org/abs/alg-geom/9702016
[ "alg-geom", "math.AG" ]
alg-geom/9702016
Miles Reid
Miles Reid (Nagoya and Warwick)
McKay correspondence
V2 cured 2 misguided crossreferences and some errors of punctuation. This v3 gives references sent in by listeners to this network, and centres the graphics, a triumph of mind over computer manual!
null
null
Proc of Kinosaki conference (Nov 1996), and Warwick preprint 1997
null
This is a rough write-up of my lecture at Kinosaki and two lectures at RIMS workshops in Dec 1996, on work in progress that has not yet reached any really worthwhile conclusion, but contains lots of fun calculations. History of Vafa's formula, how the McKay correspondence for finite subgroups of SL(n,C) relates to mi...
[ { "version": "v1", "created": "Tue, 25 Feb 1997 12:11:45 GMT" }, { "version": "v2", "created": "Wed, 26 Feb 1997 09:02:58 GMT" }, { "version": "v3", "created": "Fri, 28 Feb 1997 09:12:21 GMT" } ]
2016-08-30T00:00:00
[ [ "Reid", "Miles", "", "Nagoya and Warwick" ] ]
alg-geom
\section{Introduction}\label{sec:intro} \begin{conjecture}[since 1992]\label{conj:1992} $G\subset\SL(n,\C)$ is a finite subgroup. Assume that the quotient $X=\C^n/G$ has a crepant resolution $f\colon Y\to X$ (this just means that $K_Y=0$, so that $Y$ is a ``noncompact Calabi--Yau manifold''). Then there exist ``natur...
1997-02-03T09:31:26
9702
alg-geom/9702003
en
https://arxiv.org/abs/alg-geom/9702003
[ "alg-geom", "math.AG" ]
alg-geom/9702003
Tohsuke Urabe
Tohsuke Urabe (Department of Mathematics Tokyo Metropolitan University, Hachioji-shi, Tokyo, Japan)
Dual varieties and the duality of the second fundamental form
LaTeX2e+AmsLaTeX. 3 pages. This manuscript was submitted to Proceedings of Symposium Real Analytic and Algebraic Singularities(IS(J held at Nagoya University in September - October, 1996. Adobe PDF version is available also at http://urabe-lab.math.metro-u.ac.jp/
null
null
null
null
First, we consider a compact real-analytic irreducible subvariety $M$ in a sphere and its dual variety $M^\vee$. We explain that two matrices of the second fundamental forms for both varieties $M$ and $M^\vee$ can be regarded as the inverse matrices of each other. Also generalization in hyperbolic space is explained....
[ { "version": "v1", "created": "Mon, 3 Feb 1997 08:32:45 GMT" } ]
2008-02-03T00:00:00
[ [ "Urabe", "Tohsuke", "", "Department of Mathematics Tokyo Metropolitan\n University, Hachioji-shi, Tokyo, Japan" ] ]
alg-geom
\section{Spherical case} \label{sphere} In this article I would like to explain main ideas in my recent results on duality of the second fundamental form. (Urabe\cite{{urabe;dual}}.) Theory of dual varieties in the complex algebraic geometry is very interesting. (Griffiths and Harris~\cite{griffiths-harris;geo}, K...
1997-02-27T21:41:37
9702
alg-geom/9702019
en
https://arxiv.org/abs/alg-geom/9702019
[ "alg-geom", "math.AG" ]
alg-geom/9702019
Alan Durfee
Alan H. Durfee
Five Definitions of Critical Point at Infinity
20 pages, Latex, 4 figures
null
null
null
null
This survey paper discusses five equivalent ways of defining a ``critical point at infinity'' for a complex polynomial of two variables.
[ { "version": "v1", "created": "Thu, 27 Feb 1997 20:41:22 GMT" } ]
2008-02-03T00:00:00
[ [ "Durfee", "Alan H.", "" ] ]
alg-geom
\section{#1}} \newcounter{mycounter}[section] \renewcommand{\themycounter}{\arabic{section}.\arabic{mycounter}} \newenvironment{theorem}% {\medskip \refstepcounter{mycounter} {\bf \noindent Theorem \themycounter. \ } \begin{em} }% {\end{em} \medskip } \newenvironment{proposition}% {\medskip \refstepcou...
1997-02-27T07:20:18
9702
alg-geom/9702018
en
https://arxiv.org/abs/alg-geom/9702018
[ "alg-geom", "math.AG" ]
alg-geom/9702018
Furuya Masako
Masako Furuya
On $\delta_m$ constant locus of versal deformations of nondegenerate hypersurface simple K3 singularities
AMS-LaTeX v1.2, 35 pages with 5 figures
null
null
null
null
Hypersurface simple K3 singularities defined by nondegenerate quasi-homogeneous polynomials are classified into ninety five classes in term of the weight of the polynomial by T. Yonemura. We consider versal deformations of them. It has been conjectured that the stratum $\mu$ =const of the versal deformation of any no...
[ { "version": "v1", "created": "Thu, 27 Feb 1997 06:18:48 GMT" } ]
2008-02-03T00:00:00
[ [ "Furuya", "Masako", "" ] ]
alg-geom
\section*{Introduction} Simple $K3$ singularities are regarded as natural generalizations in three-dimensional case of simple elliptic singularities. The notion of a simple $K3$ singularity was defined by S. Ishii and K. Watanabe [IW] as a three-dimensional Gorenstein purely elliptic singularity of (0,2)-type, ...
1997-02-20T17:14:20
9702
alg-geom/9702004
en
https://arxiv.org/abs/alg-geom/9702004
[ "alg-geom", "math.AG" ]
alg-geom/9702004
Alice Silverberg
A. Silverberg and Yu. G. Zarhin
Semistable reduction of abelian varieties over extensions of small degree
LaTeX2e
null
null
null
null
We obtain necessary and sufficient conditions for abelian varieties to acquire semistable reduction over fields of low degree. Our criteria are expressed in terms of torsion points of small order defined over unramified extensions.
[ { "version": "v1", "created": "Mon, 3 Feb 1997 20:20:45 GMT" }, { "version": "v2", "created": "Thu, 20 Feb 1997 16:14:15 GMT" } ]
2016-08-30T00:00:00
[ [ "Silverberg", "A.", "" ], [ "Zarhin", "Yu. G.", "" ] ]
alg-geom
\section{Introduction} In this paper we obtain criteria for abelian varieties to acquire semistable reduction over fields of certain given (small) degrees. Our criteria are expressed in terms of unramified torsion points. Suppose that $X$ is an abelian variety defined over a field $F$, and $n$ is a positive intege...
1997-02-06T20:31:38
9702
alg-geom/9702008
en
https://arxiv.org/abs/alg-geom/9702008
[ "alg-geom", "math.AG" ]
alg-geom/9702008
Eleny-Nicoleta Ionel
Eleny-Nicoleta Ionel, Thomas H. Parker
The Gromov Invariants of Ruan-Tian and Taubes
AMS-LaTeX, 11 pages
null
null
null
null
Taubes has recently defined Gromov invariants for symplectic four-manifolds and related them to the Seiberg-Witten invariants. Independently, Ruan and Tian defined symplectic invariants based on ideas of Witten. In this note, we show that Taubes' Gromov invariants are equal to certain combinations of Ruan-Tian invari...
[ { "version": "v1", "created": "Thu, 6 Feb 1997 19:31:31 GMT" } ]
2008-02-03T00:00:00
[ [ "Ionel", "Eleny-Nicoleta", "" ], [ "Parker", "Thomas H.", "" ] ]
alg-geom
\section{Gromov Invariants} Fix a closed symplectic four-manifold $(X,\omega)$. Following the ideas of Gromov and Donaldson, one can define symplectic invariants by introducing an almost complex structure $J$ and counting (with orientation) the number of $J$-holomorphic curves on $X$ satisfying certain constrain...
1993-12-14T14:07:14
9312
alg-geom/9312007
en
https://arxiv.org/abs/alg-geom/9312007
[ "alg-geom", "math.AG" ]
alg-geom/9312007
null
Gerd Dethloff, Georg Schumacher, Pit-Mann Wong
Hyperbolicity of the complement of plane algebraic curves
LaTeX
Amer. J. Math. 117, 573-599 (1995)
null
null
null
The paper is a contribution of the conjecture of Kobayashi that the complement of a generic plain curve of degree at least five is hyperbolic. The main result is that the complement of a generic configuration of three quadrics is hyperbolic and hyperbolically embedded as well as the complement of two quadrics and a l...
[ { "version": "v1", "created": "Tue, 14 Dec 1993 13:04:27 GMT" } ]
2014-12-01T00:00:00
[ [ "Dethloff", "Gerd", "" ], [ "Schumacher", "Georg", "" ], [ "Wong", "Pit-Mann", "" ] ]
alg-geom
\section{Introduction} Hyperbolic manifolds have been studied in complex analysis as the generalizations of hyperbolic Riemann surfaces to higher dimensions. Moreover, the theory of hyperbolic manifolds is closely related to other areas (cf.\ eg. \cite{LA1}). However, only very few quasi-projective (non closed) hyper...
1996-02-27T06:25:20
9312
alg-geom/9312011
en
https://arxiv.org/abs/alg-geom/9312011
[ "alg-geom", "math.AG" ]
alg-geom/9312011
Charles Walter
Charles H. Walter
Components of the Stack of Torsion-Free Sheaves of Rank 2 on Ruled Surfaces
16 pages, LATeX 2.09
Math. Ann. 301 (1995), 699-715
null
null
null
Let S be a ruled surface without sections of negative self-intersection. We classify the irreducible components of the moduli stack of torsion-free sheaves of rank 2 sheaves on S. We also classify the irreducible components of the Brill-Noether loci in Hilb^N(P1xP1) given by W_N^0(D)={[X] | h^1(I_X(D)) >= 1 } for D a...
[ { "version": "v1", "created": "Mon, 20 Dec 1993 15:03:46 GMT" } ]
2008-02-03T00:00:00
[ [ "Walter", "Charles H.", "" ] ]
alg-geom
\section{\@startsection{section}{1}{\z@}{-3.25ex plus -1ex minus -.2ex}{1.5ex plus .2ex}{\large\bf}} \def\subsection{\@startsection {subsection}{2}{\z@}{3.25ex plus 1ex minus .2ex}{-0.5em}{\normalsize\sl}} \def\subsubsection{\@startsection {subsubsection}{3}{\z@}{3.25ex plus 1ex minus .2ex}{-0.5em}{\normalsize\sl}} ...
1994-11-07T06:20:07
9312
alg-geom/9312004
en
https://arxiv.org/abs/alg-geom/9312004
[ "alg-geom", "math.AG" ]
alg-geom/9312004
Alexander Polischuk
A. Polishchuk
On Koszul property of the homogeneous coordinate ring of a curve
17 pages, Latex
null
null
null
null
The following corollary has been added: for general tetragonal curve $C$ of genus $g\ge 9$ the homogeneous coordinate ring of $C$ defined by the line bundle $K(-T)$, where $K$ is the canonical class, $T$ is the tetragonal series, is Koszul. Also some misprints are corrected.
[ { "version": "v1", "created": "Wed, 8 Dec 1993 23:25:56 GMT" }, { "version": "v2", "created": "Fri, 4 Nov 1994 18:27:46 GMT" } ]
2008-02-03T00:00:00
[ [ "Polishchuk", "A.", "" ] ]
alg-geom
\section{Introduction} This paper is devoted to Koszul property of the homogeneous coordinate algebra of a smooth complex algebraic curve in the projective space (the notion of a Koszul algebra is some homological refinement of the notion of a quadratic algebra, for precise definition see next section). It grew out f...
1993-12-20T15:58:43
9312
alg-geom/9312010
en
https://arxiv.org/abs/alg-geom/9312010
[ "alg-geom", "math.AG" ]
alg-geom/9312010
Charles Walter
Charles H. Walter
On the Harder-Narasimhan Filtration for Coherent Sheaves on P2: I
14 pages, LATeX 2.09
null
null
null
null
Let E be a torsion-free sheaf on P2. We give an effective method which uses the Hilbert function of E to construct a weak version of the Harder-Narasimhan filtration of a torsion-free sheaf on P2 subject only to the condition that E be sufficiently general among sheaves with that Hilbert function. This algorithm uses...
[ { "version": "v1", "created": "Mon, 20 Dec 1993 15:00:43 GMT" } ]
2008-02-03T00:00:00
[ [ "Walter", "Charles H.", "" ] ]
alg-geom
\section{\@startsection{section}{1}{\z@}{-3.25ex plus -1ex minus -.2ex}{1.5ex plus .2ex}{\large\bf}} \def\subsection{\@startsection {subsection}{2}{\z@}{3.25ex plus 1ex minus .2ex}{-0.5em}{\normalsize\sl}} \def\subsubsection{\@startsection {subsubsection}{3}{\z@}{3.25ex plus 1ex minus .2ex}{-0.5em}{\normalsize\sl}} ...
1993-12-14T14:10:39
9312
alg-geom/9312008
en
https://arxiv.org/abs/alg-geom/9312008
[ "alg-geom", "math.AG" ]
alg-geom/9312008
null
Gerd Dethloff, Georg Schumacher, Pit-Mann Wong
On the Hyperbolicity of the Complements of Curves in Algebraic Surfaces: The Three Component Case
26 pages, LaTeX
Duke Math. J. 78, 193-212 (1995)
null
null
null
The paper is a contribution to the conjecture of Kobayashi that the complement of a generic curve in the projective plane is hyperbolic, provided the degree is at least five. Previously the authors treated the cases of two quadrics and a line and three quadrics. The main results are Let C be the union of three curves...
[ { "version": "v1", "created": "Tue, 14 Dec 1993 13:06:20 GMT" } ]
2014-12-01T00:00:00
[ [ "Dethloff", "Gerd", "" ], [ "Schumacher", "Georg", "" ], [ "Wong", "Pit-Mann", "" ] ]
alg-geom
\section{Introduction} In complex analysis hyperbolic manifolds have been studied extensively, with close relationships to other areas (cf.\ eg. \cite{LA1}). Hyperbolic manifolds are generalizations of hyperbolic Riemann surfaces to higher dimensions. Despite the fact that the general theory of hyperbolic manifolds is ...
1993-12-14T12:40:04
9312
alg-geom/9312006
en
https://arxiv.org/abs/alg-geom/9312006
[ "alg-geom", "math.AG" ]
alg-geom/9312006
Fabrizio Broglia
F. Acquistapace, F.Broglia, M.Pilar Velez
An algorithmic criterion for basicness in dimension 2
23 pages, amslatex (+bezier.sty) report: 1.89.(766) october 1993
null
null
null
null
We give a constructive procedure to check basicness of open (or closed) semialgebraic sets in a compact, non singular, real algebraic surface $X$. It is rather clear that if a semialgebraic set $S$ can be separated from each connected component of $X\setminus(S\cup\frz S)$ (when $\frz S$ stands for the Zariski closur...
[ { "version": "v1", "created": "Tue, 14 Dec 1993 10:58:46 GMT" } ]
2008-02-03T00:00:00
[ [ "Acquistapace", "F.", "" ], [ "Broglia", "F.", "" ], [ "Velez", "M. Pilar", "" ] ]
alg-geom
\section*{Introduction.} In this paper we give a constructive procedure to check basicness of open (or closed) semialgebraic sets in a compact, non singular, real algebraic surface $X$. It is rather clear that if a semialgebraic set $S$ can be separated from each connected component of $X\setminus(S\cup\partial _{\rm ...
1994-01-24T21:31:29
9312
alg-geom/9312012
en
https://arxiv.org/abs/alg-geom/9312012
[ "alg-geom", "math.AG" ]
alg-geom/9312012
Israel Vainsencher
Israel Vainsencher
Enumeration of $n$-fold tangent hyperplanes to a surface
34 pages, Latex (Corrects Latex errors of previous version, minor changes)
null
null
null
null
For each $1\leq n\leq6$ we present formulas for the number of $n-$nodal curves in an $n-$dimensional linear system on a smooth, projective surface. This yields in particular the numbers of rational curves in the system of hyperplane sections of a generic $K3-$surface imbedded in \p{n} by a complete system of curves o...
[ { "version": "v1", "created": "Tue, 21 Dec 1993 21:29:13 GMT" }, { "version": "v2", "created": "Mon, 24 Jan 1994 14:43:01 GMT" } ]
2008-02-03T00:00:00
[ [ "Vainsencher", "Israel", "" ] ]
alg-geom
\section{Introduction} \normalsize The purpose of this article is to present formulas for the number of $n-$nodal curves in an $n-$dimensional linear system on a smooth, projective surface for $1\leq n\leq6$. The method also yields formulas for the number of multi--tangent planes to a hypersurface. In particular, it e...
1996-06-03T11:04:21
9606
alg-geom/9606001
en
https://arxiv.org/abs/alg-geom/9606001
[ "alg-geom", "math.AC", "math.AG" ]
alg-geom/9606001
Peter Schenzel
Peter Schenzel
Descent from the form ring and Buchsbaum rings
To appear in Comm. Algebra Latex2e
null
null
null
null
There is a spectral sequence technique in order to estimate the local cohomology of a ring by the local cohomology of a certain form ring. As applications there are information on the descent of homological properties (Cohen-Macaulay, Buchsbaum etc.) from the form ring to the ring itself. In the case of Buchsbaum rin...
[ { "version": "v1", "created": "Mon, 3 Jun 1996 10:00:59 GMT" } ]
2008-02-03T00:00:00
[ [ "Schenzel", "Peter", "" ] ]
alg-geom
\section{Introduction and Main Results} One of the major problems in commutative algebra is to recover information about a commutative ring $A$ from known properties of the form ring $G := G_A(\mathfrak q) = \oplus_{n\geq 0} {\mathfrak q}^n/{\mathfrak q}^{n+1}$ with respect to some ideal $\mathfrak q$ of $A$. Ther...
1996-06-20T17:00:23
9606
alg-geom/9606014
en
https://arxiv.org/abs/alg-geom/9606014
[ "alg-geom", "math.AG" ]
alg-geom/9606014
null
Sheldon Katz, Zhenbo Qin, and Yongbin Ruan
Composition law and Nodal genus-2 curves in P^2
13 pages, AMS-TeX
null
null
OSU Math 1996-18
null
Recently, there has been great interest in the application of composition laws to problems in enumerative geometry. Using the moduli space of stable maps, we compute the number of irreducible, reduced, nodal, degree-$d$ genus-$2$ plane curves whose normalization has a fixed complex structure and which pass through $3...
[ { "version": "v1", "created": "Thu, 20 Jun 1996 15:01:23 GMT" } ]
2008-02-03T00:00:00
[ [ "Katz", "Sheldon", "" ], [ "Qin", "Zhenbo", "" ], [ "Ruan", "Yongbin", "" ] ]
alg-geom
\section{1. Introduction} Enumerative algebraic geometry is an old field of algebraic geometry. There are many fascinating problems going back more than a hundred years to the Italian school. The most famous one is perhaps the counting problem for the number of holomorphic curves in $\Pee^2$. There are in fact two...
1996-09-28T13:10:14
9606
alg-geom/9606010
en
https://arxiv.org/abs/alg-geom/9606010
[ "alg-geom", "math.AG", "math.QA", "q-alg" ]
alg-geom/9606010
Vladimir Hinich
Vladimir Hinich
Descent of Deligne groupoids
Minor corrections made AMSLaTeX v 1.2 (Compatibility mode)
null
null
null
null
To any non-negatively graded dg Lie algebra $g$ over a field $k$ of characteristic zero we assign a functor $\Sigma_g: art/k \to Kan$ from the category of commutative local artinian $k$-algebras with the residue field $k$ to the category of Kan simplicial sets. There is a natural homotopy equivalence between $\Sigma_...
[ { "version": "v1", "created": "Tue, 11 Jun 1996 07:55:20 GMT" }, { "version": "v2", "created": "Wed, 25 Sep 1996 17:22:16 GMT" }, { "version": "v3", "created": "Sat, 28 Sep 1996 11:07:28 GMT" } ]
2016-08-30T00:00:00
[ [ "Hinich", "Vladimir", "" ] ]
alg-geom
\section{Introduction} \subsection{} \label{i1} Let $\fg$ be a dg Lie algebra over a field $k$ of characteristic zero concentrated in non-negative degrees. The algebra $\fg$ defines a functor $$ \CC_{\fg}:\art/k\to\Grp$$ from the category of local artinian $k$-algebras with the residue field $k$ to the category of gro...
2009-11-28T03:16:12
9606
alg-geom/9606006
en
https://arxiv.org/abs/alg-geom/9606006
[ "alg-geom", "math.AG" ]
alg-geom/9606006
Dmitri O. Orlov
Dmitri Orlov
Equivalences of derived categories and K3 surfaces
28 pages, LaTeX file
J. Math. Sci. (New York) 84 (1997), no. 5, 1361--1381
null
null
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
We consider derived categories of coherent sheaves on smooth projective varieties. We prove that any equivalence between them can be represented by an object on the product. Using this, we give a necessary and sufficient condition for equivalence of derived categories of two K3 surfaces.
[ { "version": "v1", "created": "Fri, 7 Jun 1996 12:29:42 GMT" }, { "version": "v2", "created": "Tue, 11 Jun 1996 10:37:02 GMT" }, { "version": "v3", "created": "Fri, 1 Nov 1996 12:54:27 GMT" }, { "version": "v4", "created": "Wed, 17 Dec 1997 13:00:12 GMT" }, { "ver...
2009-11-28T00:00:00
[ [ "Orlov", "Dmitri", "" ] ]
alg-geom
\section*{Introduction} Let $\db{X}$ be the bounded derived category of coherent sheaves on a smooth projective variety $X.$ The category $\db{X}$ has the structure of a triangulated category (see \cite{Ver}, \cite{GM}). We shall consider $\db{X}$ as a triangulated category. In this paper we are concerned with the pr...
1996-06-06T13:40:26
9606
alg-geom/9606003
en
https://arxiv.org/abs/alg-geom/9606003
[ "alg-geom", "math.AG" ]
alg-geom/9606003
V. Batyrev
Victor V. Batyrev, Yuri Tschinkel
Height Zeta Functions of Toric Varieties
27 pages, AMS-LaTeX
null
null
LMENS-96-9
null
We investigate analytic properties of height zeta functions of toric varieties. Using the height zeta functions, we prove an asymptotic formula for the number of rational points of bounded height with respect to an arbitrary line bundle whose first Chern class is contained in the interior of the cone of effective div...
[ { "version": "v1", "created": "Thu, 6 Jun 1996 11:36:04 GMT" } ]
2008-02-03T00:00:00
[ [ "Batyrev", "Victor V.", "" ], [ "Tschinkel", "Yuri", "" ] ]
alg-geom
\section{Introduction} \bigskip Let $X$ be a $d$-dimensional algebraic variety defined over a number field $F$. Denote by ${\cal L}=(L,\{\|\cdot\|_v\})$ a metrized line bundle on $X$ , i.e. a line bundle $L$ together with a family of $v$-adic metrics, where $v$ runs over the set ${\operatorname{Val} }(F)$ of all va...
1997-04-23T16:41:51
9606
alg-geom/9606019
en
https://arxiv.org/abs/alg-geom/9606019
[ "alg-geom", "dg-ga", "hep-th", "math.AG", "math.DG" ]
alg-geom/9606019
Misha Verbitsky
Dmitry Kaledin, Misha Verbitsky
Non-Hermitian Yang-Mills connections
48 pages, LaTeX 2e
Selecta Math. 4 (1998) 279-320
null
null
null
We study Yang-Mills connections on holomorphic bundles over complex K\"ahler manifolds of arbitrary dimension, in the spirit of Hitchin's and Simpson's study of flat connections. The space of non-Hermitian Yang-Mills (NHYM) connections has dimension twice the space of Hermitian Yang-Mills connections, and is locally ...
[ { "version": "v1", "created": "Mon, 1 Jul 1996 00:01:13 GMT" } ]
2008-02-03T00:00:00
[ [ "Kaledin", "Dmitry", "" ], [ "Verbitsky", "Misha", "" ] ]
alg-geom
\section{Introduction.} \subsection{An overview} In this paper we study non-Hermitian Yang-Mills (NHYM) connections on a complex vector bundle ${\cal B}$ over a K\"ahler manifold. By definition, a connection $\nabla$ in ${\cal B}$ is Yang-Mills if its curvature $\Theta$ satisfies \begin{equation} \label{intro-Yan...
1996-06-27T15:32:07
9606
alg-geom/9606017
fr
https://arxiv.org/abs/alg-geom/9606017
[ "alg-geom", "math.AG" ]
alg-geom/9606017
Emmanuel Ullmo
Emmanuel Ullmo
Positivite et discretion des points algebriques des courbes
null
null
null
null
null
We prove the discreteness of algebraic points (with respect to the Neron-Tate height) on a curve of genus greater than one embedded in his jacobian. This result was conjectured by Bogomolov. We also prove the positivity of the self intersection of the admissible dualizing sheaf.
[ { "version": "v1", "created": "Thu, 27 Jun 1996 13:32:11 GMT" } ]
2008-02-03T00:00:00
[ [ "Ullmo", "Emmanuel", "" ] ]
alg-geom
\section{Introduction} Soient $K$ un corps de nombres et $\overline{K}$ sa cl\^oture alg\'ebrique. Soient $X_K$ une courbe propre, lisse, g\'eom\'etriquement connexe de genre $g\ge 2$ sur $K$ et $J$ sa jacobienne. Soit $D_0$ un diviseur de degr\'e 1 sur $X$ et $\phi_{D_0}$ le plongement de $X_K$ dans $J$ d\'efini p...
1996-11-15T12:20:43
9606
alg-geom/9606009
en
https://arxiv.org/abs/alg-geom/9606009
[ "alg-geom", "math.AG" ]
alg-geom/9606009
Francisco Jose Plaza Martin
A. \'Alvarez V\'azquez, J. M. Mu\~noz Porras, F. J. Plaza Mart\'in
The algebraic formalism of soliton equations over arbitrary base fields
Minor changes in Section 5 and References
Variedades Abelianas y Funciones Theta, Ap. Mat. Serie Investigaci\'on No. 13, Sociedad Matem\'atica Mexicana, M\'exico 1998
null
null
null
The aim of this paper is to offer an algebraic construction of infinite-dimensional Grassmannians and determinant bundles (and therefore valid for arbitrary base fields). As an application we construct the $\tau$-function and formal Baker-Akhiezer functions over arbitrary fields, by proving the existence of a ``forma...
[ { "version": "v1", "created": "Mon, 10 Jun 1996 18:09:23 GMT" }, { "version": "v2", "created": "Fri, 15 Nov 1996 10:19:15 GMT" } ]
2016-08-15T00:00:00
[ [ "Vázquez", "A. Álvarez", "" ], [ "Porras", "J. M. Muñoz", "" ], [ "Martín", "F. J. Plaza", "" ] ]
alg-geom
\section{Introduction} The aim of this paper is to offer an algebraic construction of infinite-dimensional Grassmannians and determinant bundles. As an application we construct the $\tau$-function and formal Baker-Akhiezer functions over arbitrary fields, by proving the existence of a ``formal geometry'' of local cur...
1996-06-07T13:25:43
9606
alg-geom/9606007
en
https://arxiv.org/abs/alg-geom/9606007
[ "alg-geom", "math.AG" ]
alg-geom/9606007
Joost van Hamel
Fr\'ed\'eric Mangolte and Joost van Hamel
Algebraic cycles and topology of real Enriques surfaces
18 pages AMS-LaTeX v 1.2
null
null
null
null
For a real Enriques surface Y we prove that every homology class in H_1(Y(R), Z/2) can be represented by a real algebraic curve if and only if all connected components of Y(R) are orientable. Furthermore, we give a characterization of real Enriques surfaces which are Galois-Maximal and/or Z-Galois-Maximal and we dete...
[ { "version": "v1", "created": "Fri, 7 Jun 1996 11:20:04 GMT" } ]
2008-02-03T00:00:00
[ [ "Mangolte", "Frédéric", "" ], [ "van Hamel", "Joost", "" ] ]
alg-geom
\subsubsection*{Acknowledgements}}{\par} \begin{document} \title[Real Enriques surfaces]{Algebraic cycles and topology \\ of real Enriques surfaces} \author{Fr\'ed\'eric Mangolte\and Joost van Hamel} \keywords{Algebraic cycles, Real algebraic surfaces, Enriques surfaces, Galois-Maximality} \subjclass{14C25 14P25...
1996-06-10T14:01:56
9606
alg-geom/9606008
en
https://arxiv.org/abs/alg-geom/9606008
[ "alg-geom", "math.AG" ]
alg-geom/9606008
Michal Kwiecinski
Michal Kwiecinski and Piotr Tworzewski
Finite sets in fibres of holomorphic maps
LaTeX v. 2.09, 16 pages
null
null
IMUJ preprint 1996/08, Jagiellonian Univ., Krakow
null
We consider the maximal number of arbitrary points in a special fibre that can be simultaneously approached by points in one sequence of general fibres. Several results about this topological invariant and their applications describe the structure of holomorphic maps. In particular, we get a lower bound on the number...
[ { "version": "v1", "created": "Mon, 10 Jun 1996 12:03:01 GMT" } ]
2008-02-03T00:00:00
[ [ "Kwiecinski", "Michal", "" ], [ "Tworzewski", "Piotr", "" ] ]
alg-geom
\section{Introduction.} From the work of Thom \cite{Thom}, Fukuda \cite{Fukuda} and Nakai \cite{Nakai}, it follows that one cannot stratify arbitrary complex algebraic maps so as to have local topological triviality, such as in the case of Whitney stratified spaces. Indeed, an arbitrary complex map can have a locally...
1997-04-01T15:34:01
9606
alg-geom/9606015
en
https://arxiv.org/abs/alg-geom/9606015
[ "alg-geom", "math.AG" ]
alg-geom/9606015
Ines Quandt
Ines Quandt
On a relative version of the Krichever correspondence
59 pages LaTeX with inputs of AMSTeX; In addition to some corrections the main change consists in the extension of the Krichever correspondence to all locally noetherian base schemes
Bayreuther Mathematische Schriften 52 (1997), p.1-74
null
null
null
For a given base scheme, a correspondence is established between a class of sheaves on curves over this base scheme and certain points of infinite Grassmannians. This equivalence extends to a characterization of commutative algebras of ordinary differential operators with coefficients in the ring of formal power seri...
[ { "version": "v1", "created": "Fri, 21 Jun 1996 07:29:24 GMT" }, { "version": "v2", "created": "Tue, 1 Apr 1997 13:36:31 GMT" } ]
2008-02-03T00:00:00
[ [ "Quandt", "Ines", "" ] ]
alg-geom
\section*{Preface} This PhD thesis is the result of my work in the Graduiertenkolleg "Geometrie und Nichtlineare Analysis" at Humboldt University Berlin and in the DFG project KU 770/1-3. \vspace{0.5cm}\\ It is published in the {\em Bayreuther Mathematische Schriften} {\bf 52} (1997), p.1-74. \vspace{0.5cm}\\ At ...
1996-06-06T09:45:23
9606
alg-geom/9606002
en
https://arxiv.org/abs/alg-geom/9606002
[ "alg-geom", "math.AG" ]
alg-geom/9606002
Rita Pardini
Rita Pardini
On the period map for abelian covers of algebraic varieties
LaTeX, 17 pages
null
null
null
null
We show that infinitesimal Torelli for $n$-forms holds for abelian covers of algebraic varieties of dimension $n\ge 2$, under some explicit ampleness assumptions on the building data of the cover. Moreover, we prove a variational Torelli result for some families of abelian covers.
[ { "version": "v1", "created": "Thu, 6 Jun 1996 08:38:16 GMT" } ]
2008-02-03T00:00:00
[ [ "Pardini", "Rita", "" ] ]
alg-geom
\section{Introduction} \setcounter{defn}{0} \setcounter{equation}{0} This paper is devoted to the study of the period map for abelian covers of smooth projective varieties of dimension $n\ge 2$. Our viewpoint is very close to that of Green in \cite{suffampio}, namely we look for results that hold for abelian covers...
1995-10-12T06:39:56
9507
alg-geom/9507010
en
https://arxiv.org/abs/alg-geom/9507010
[ "alg-geom", "math.AG" ]
alg-geom/9507010
Leonid Positselski
Leonid Positselski and Alexander Vishik
Koszul duality and Galois cohomology
AMS-LaTeX v.1.1, 10 pages, no figures. Replaced for tex code correction (%&amslplain added) by request of www-admin
Math. Research Letters 2 (1995), no.6, p.771-781
10.4310/MRL.1995.v2.n6.a8
null
null
It it shown that the Bloch-Kato conjecture on the norm residue homomorphism $K^M(F)/l \to H^*(G_F,Z/l)$ follows from its (partially known) low-degree part under the assumption that the Milnor K-theory algebra $K^M(F)/l$ modulo $l$ is Koszul. This conclusion is a case of a general result on the cohomology of nilpotent...
[ { "version": "v1", "created": "Tue, 11 Jul 1995 23:07:32 GMT" }, { "version": "v2", "created": "Thu, 31 Aug 1995 02:00:06 GMT" } ]
2013-10-29T00:00:00
[ [ "Positselski", "Leonid", "" ], [ "Vishik", "Alexander", "" ] ]
alg-geom
\section{#1}\medskip} \newcommand{\operatorname{coker}}{\operatorname{coker}} \newcommand{\operatorname{id}}{\operatorname{id}} \newcommand{\operatorname{char}}{\operatorname{char}} \newcommand{\operatorname{Hom}}{\operatorname{Hom}} \newcommand{\operatorname{Tor}}{\operatorname{Tor}} \newcommand{\operatorname{Ext}}{\...
1995-07-26T06:20:13
9507
alg-geom/9507014
en
https://arxiv.org/abs/alg-geom/9507014
[ "alg-geom", "math.AG" ]
alg-geom/9507014
Leonid Positselski
Leonid Positselski
All strictly exceptional collections in $D^b_{coh}(P^m)$ consist of vector bundles
LaTeX 2e, 6 pages, no figures; replaced to correct formatting (amslatex to latex2e transition) and several misprints, no other changes
null
null
null
http://arxiv.org/licenses/nonexclusive-distrib/1.0/
It is proved that any strictly exceptional collection generating the derived category of coherent sheaves on a smooth projective variety X with \rk K_0(X) = \dim X + 1 constists of locally free sheaves up to a common shift.
[ { "version": "v1", "created": "Wed, 26 Jul 1995 01:38:39 GMT" }, { "version": "v2", "created": "Sat, 26 Oct 2013 18:12:41 GMT" } ]
2013-10-29T00:00:00
[ [ "Positselski", "Leonid", "" ] ]
alg-geom
\section{Introduction} Let $\k$ be a field and ${\cal D}$ be a $\k$-linear triangulated category; we will denote, as usually, $\operatorname{Hom}^i(X,Y)=\operatorname{Hom}(X,Y[i])$ and $\operatorname{Hom^{\scriptscriptstyle\bullet}}(X,Y)=\bigoplus_i\operatorname{Hom}^i(X,Y)$. An object $E\in{\cal O}b\>{\cal D}$ is c...
1996-03-08T06:56:05
9507
alg-geom/9507002
en
https://arxiv.org/abs/alg-geom/9507002
[ "alg-geom", "math.AG" ]
alg-geom/9507002
Christoph Sorger
Yves Laszlo and Christoph Sorger
The line bundles on the stack of parabolic $G$-bundles over curves and their sections
LaTeX2e with package amsart, 31 pages, no figures. This is a revised version of our paper (mainly, the introduction and the section on pfaffians have been changed). The TeX file, as well as the .dvi and .ps files are also available at ftp://ftp.mathp7.jussieu.fr/pub/sorger
null
null
null
null
Let $X$ be a smooth, complete and connected curve and $G$ be a simple and simply connected algebraic group over $\comp$. We calculate the Picard group of the moduli stack of quasi-parabolic $G$-bundles and identify the spaces of sections of its members to the conformal blocs of Tsuchiya, Ueno and Yamada. We describe ...
[ { "version": "v1", "created": "Wed, 5 Jul 1995 08:33:53 GMT" }, { "version": "v2", "created": "Tue, 10 Oct 1995 12:39:17 GMT" }, { "version": "v3", "created": "Tue, 5 Mar 1996 23:25:37 GMT" } ]
2008-02-03T00:00:00
[ [ "Laszlo", "Yves", "" ], [ "Sorger", "Christoph", "" ] ]
alg-geom
\section{Introduction.} \subsection{}\label{th:Pic} Fix a simple and simply connected algebraic group $G$ over $k=\comp$ and a Borel subgroup $B\subset G$. Let $X$ be a smooth, complete and connected curve over $k$ and $p_{1},\dots,p_{n}$ be distinct points of $X$, labeled by standard (\ie containing $B$) parabolic su...
1995-08-09T06:20:26
9507
alg-geom/9507017
en
https://arxiv.org/abs/alg-geom/9507017
[ "alg-geom", "math.AG" ]
alg-geom/9507017
Ron Donagi
Ron Donagi and Eyal Markman
Spectral curves, algebraically completely integrable Hamiltonian systems, and moduli of bundles
Latex, We restore the page numbers which were inadvertently omitted. The content stayed the same
null
null
null
null
This is the expanded text of a series of CIME lectures. We present an algebro-geometric approach to integrable systems, starting with those which can be described in terms of spectral curves. The prototype is Hitchin's system on the cotangent bundle of the moduli space of stable bundles on a curve. A variant involvin...
[ { "version": "v1", "created": "Mon, 31 Jul 1995 23:00:47 GMT" }, { "version": "v2", "created": "Tue, 8 Aug 1995 15:35:29 GMT" } ]
2008-02-03T00:00:00
[ [ "Donagi", "Ron", "" ], [ "Markman", "Eyal", "" ] ]
alg-geom
\section{Introduction} \label{ch1} The purpose of these notes is to present an algebro-geometric point of view on several interrelated topics, all involving integrable systems in symplectic-algebro-geometric settings. These systems range from some very old examples, such as the geodesic flow on an ellipsoid, th...
1995-07-31T06:20:14
9507
alg-geom/9507015
en
https://arxiv.org/abs/alg-geom/9507015
[ "alg-geom", "math.AG" ]
alg-geom/9507015
Brendan Hassett
Brendan Hassett
Correlation for Surfaces of General Type
AMSLaTeX. This version contains some minor corrections, and additions to the references
null
null
null
null
The main geometric result of this paper is that given any family of surfaces of general type f:X-->B, for sufficiently large n the fiber product X^n_B dominates a variety of general type. This result is especially interesting when it is combined with Lang's Conjecture. This states that for a variety V of general type...
[ { "version": "v1", "created": "Wed, 26 Jul 1995 23:27:19 GMT" }, { "version": "v2", "created": "Sun, 30 Jul 1995 16:50:12 GMT" } ]
2008-02-03T00:00:00
[ [ "Hassett", "Brendan", "" ] ]
alg-geom
\section{Introduction} The purpose of this paper is to prove the following theorem: \begin{thm}[Correlation Theorem for Surfaces] Let $f:X \longrightarrow B$ be a proper morphism of integral varieties, whose general fiber is an integral surface of general type. Then for $n$ sufficiently large, $X^n_B$ admits a dominan...
1995-07-20T06:20:10
9507
alg-geom/9507011
en
https://arxiv.org/abs/alg-geom/9507011
[ "alg-geom", "math.AG" ]
alg-geom/9507011
Stephan Endrass
Stephan Endrass
A Projective Surface of Degree Eight with 168 Nodes
LaTeX 2.09 with amssymbols
null
null
null
null
The estimate for the maximal number of ordinary double points of a projective surface of degree eight is improved to $168\leq\mu(8)\leq 174$ by constructing a projective surface of degree eight with 168 nodes.
[ { "version": "v1", "created": "Wed, 19 Jul 1995 14:08:27 GMT" } ]
2008-02-03T00:00:00
[ [ "Endrass", "Stephan", "" ] ]
alg-geom
\section*{Introduction} Consider algebraic surfaces in complex projective threespace ${\Bbb P}_3$, denote by a {\em node} of such a surface an ordinary double point and by $\mu\left(d\right)$ the maximal number of nodes of an algebraic surface of degree $d$ in ${\Bbb P}_3$ with no further degeneracies. This note shows ...
1995-10-02T05:20:11
9507
alg-geom/9507012
en
https://arxiv.org/abs/alg-geom/9507012
[ "alg-geom", "math.AG" ]
alg-geom/9507012
Nakajima Hiraku
Hiraku Nakajima
Heisenberg algebra and Hilbert schemes of points on projective surfaces
AMS-LaTeX v. 1.1, 16 pages
null
null
null
null
I have just replaced the first line by %&amslplain in order to be compiled by AMS-LaTeX.
[ { "version": "v1", "created": "Thu, 20 Jul 1995 05:04:25 GMT" }, { "version": "v2", "created": "Fri, 29 Sep 1995 23:03:44 GMT" } ]
2008-02-03T00:00:00
[ [ "Nakajima", "Hiraku", "" ] ]
alg-geom
\section{Introduction} The purpose of this paper is to throw a bridge between two seemingly unrelated subjects. One is the Hilbert scheme of points on projective surfaces, which has been intensively studied by various people (see e.g., \cite{Iar,ES,Got,Go-book}). The other is the infinite dimensional Heisenberg algebra...
1995-07-10T06:20:21
9507
alg-geom/9507004
en
https://arxiv.org/abs/alg-geom/9507004
[ "alg-geom", "math.AG" ]
alg-geom/9507004
Mikhail Zaidenberg
H. Flenner and M. Zaidenberg
On a class of rational cuspidal plane curves
LaTeX 30 pages, author-supplied DVI file available at http://www.math.duke.edu/preprints/95-00.dvi
null
null
Duke preprint DUKE-M-95-00
null
We obtain new examples and the complete list of the rational cuspidal plane curves $C$ with at least three cusps, one of which has multiplicity ${\rm deg}\,C - 2$. It occurs that these curves are projectively rigid. We also discuss the general problem of projective rigidity of rational cuspidal plane curves.
[ { "version": "v1", "created": "Fri, 7 Jul 1995 13:12:49 GMT" } ]
2008-02-03T00:00:00
[ [ "Flenner", "H.", "" ], [ "Zaidenberg", "M.", "" ] ]
alg-geom
\section{On multiplicity sequences} \noindent {\bf 1.1. Definition.} Let $(C, \,P) \subset ({\bf C}^2,\,P)$ be an irreducible analytic plane curve germ, and let $${\bf C}^2 = V_0 \qquad {\stackrel{\sigma_1}{\longleftarrow}} \qquad V_1 \qquad {\stackrel{\sigma_2}{\longleftarrow}} \qquad \cdots \qquad {\stackrel{\sigma_...
1995-07-10T06:20:26
9507
alg-geom/9507006
en
https://arxiv.org/abs/alg-geom/9507006
[ "alg-geom", "math.AG" ]
alg-geom/9507006
Jeroen Spandaw
Jeroen G. Spandaw
A Noether-Lefschetz theorem for vector bundles
5 pages, no figures; LaTeX2e, should also work with LaTeX 2.09 with NFSS
null
null
null
null
In this note we use the monodromy argument to prove a Noether-Lefschetz theorem for vector bundles.
[ { "version": "v1", "created": "Fri, 7 Jul 1995 14:36:41 GMT" } ]
2008-02-03T00:00:00
[ [ "Spandaw", "Jeroen G.", "" ] ]
alg-geom
\section{Introduction}\pagenumbering{arabic} Let $X$ be a smooth complex projective manifold of dimension $n$ and let $E$ be a very ample vector bundle on $X$ of rank $r$. This means that the tautological quotient line bundle $L$ on the bundle $Y={\Bbb P}(E^\ast)$ of hyperplanes in $E$ is very ample. For almost all $s...
1995-07-05T06:20:14
9507
alg-geom/9507001
en
https://arxiv.org/abs/alg-geom/9507001
[ "alg-geom", "math.AG" ]
alg-geom/9507001
Iwamoto Masayuki
Masayuki Iwamoto
General n-canonical divisors on two-dimensional smoothable semi-log-terminal singularities
AMSLaTeX v 1.1
null
null
null
null
In this paper we calculate genaral n-canonical divisors on smoothable semi-log-terminal singularities in dimension 2, in other words, the full sheaves associated to the double dual of the nth tensor power of the dualizing sheaves of these singularities. And as its application we give the inequality which bound the Go...
[ { "version": "v1", "created": "Tue, 4 Jul 1995 07:46:34 GMT" } ]
2008-02-03T00:00:00
[ [ "Iwamoto", "Masayuki", "" ] ]
alg-geom
\section{Introduction} This paper is devoted to some fundumental calculation on 2-dimensional smoothable semi-log-terminal singularities. If we study minimal or canonical models of one parameter degeneration of algebraic surfaces, we must treat singularities that appear in the central fiber. Smoothable semi-log-termin...
1995-07-10T06:20:23
9507
alg-geom/9507005
en
https://arxiv.org/abs/alg-geom/9507005
[ "alg-geom", "math.AG" ]
alg-geom/9507005
Mikhail Zaidenberg
S. Orevkov and M. Zaidenberg
On the number of singular points of plane curves
LaTeX, 24 pages with 3 figures, author-supplied DVI file available at http://www.math.duke.edu/preprints/95-00.dvi
null
null
Duke preprint DUKE-M-95-00
null
This is an extended, renovated and updated report on a joint work which the second named author presented at the Conference on Algebraic Geometry held at Saitama University, 15-17 of March, 1995. The main result is an inequality for the numerical type of singularities of a plane curve, which involves the degree of th...
[ { "version": "v1", "created": "Fri, 7 Jul 1995 13:21:11 GMT" } ]
2008-02-03T00:00:00
[ [ "Orevkov", "S.", "" ], [ "Zaidenberg", "M.", "" ] ]
alg-geom
\section{Asymptotics of the number of ordinary cusps} We start with a brief survey of known results in the simplest case of ordinary cusps. It is well known that for a nodal plane curve $D \subset {\bf P}^2$ of degree $d$ the number of nodes can be an arbitrary non--negative integer allowed by the genus formula, i...
1997-06-02T18:22:22
9612
alg-geom/9612004
en
https://arxiv.org/abs/alg-geom/9612004
[ "alg-geom", "hep-th", "math.AG" ]
alg-geom/9612004
Ezra Getzler
Ezra Getzler (Northwestern University)
Intersection theory on $\Mbar_{1,4}$ and elliptic Gromov-Witten invariants
25 pages. amslatex-1.2. This is the revised version which will appear in J. Amer. Math. Soc
null
null
MPI 96-161
null
The WDVV equation is satisfied by the genus 0 correlation functions of any topological field theory in two dimensions coupled to topological gravity, and may be used to determine the genus 0 (rational) Gromov-Witten invariants of many projective varieties (as was done for projective spaces by Kontsevich). In this p...
[ { "version": "v1", "created": "Fri, 6 Dec 1996 15:07:57 GMT" }, { "version": "v2", "created": "Mon, 2 Jun 1997 16:24:27 GMT" } ]
2008-02-03T00:00:00
[ [ "Getzler", "Ezra", "", "Northwestern University" ] ]
alg-geom
\section{Intersection theory on $\overline{\mathcal{M}}_{1,4}$} In this section, we calculate the relations among certain codimension two cycles in $\overline{\mathcal{M}}_{1,4}$; one such relation was known, and we find that there is one new one. First, we assign names to the codimension $1$ strata of $\overline{\ma...
1996-12-18T03:27:05
9612
alg-geom/9612013
en
https://arxiv.org/abs/alg-geom/9612013
[ "alg-geom", "math.AG" ]
alg-geom/9612013
Misha S. Verbitsky
Misha Verbitsky
Desingularization of singular hyperkaehler varieties II
LaTeX 2e, 15 pages. This paper can be read independently from the first part. `Desingularization part I' appeared in alg-geom/9611015
null
null
null
null
This is a second part of alg-geom/9611015. We construct a natural hyperkaehler desingularization for all singular hyperkaehler varieties. The desingularization theorem was proven in alg-geom/9611015 under additional assumption of local homogeneity. Here we show that local homogeneity is redundant: every singular hype...
[ { "version": "v1", "created": "Wed, 18 Dec 1996 02:26:57 GMT" } ]
2008-02-03T00:00:00
[ [ "Verbitsky", "Misha", "" ] ]
alg-geom
\section{Introduction} A hyperk\"ahler manifold is a Riemannian manifold with an action of a quaternion algebra $\Bbb H$ in its tangent bundle, such that for all $I\in \Bbb H$, $I^2=-1$, $I$ establishes a complex, K\"ahler structure on $M$ (see \ref{_hyperkahler_manifold_Definition_} for details). We extend this defi...
1996-12-07T21:10:17
9612
alg-geom/9612007
en
https://arxiv.org/abs/alg-geom/9612007
[ "alg-geom", "math.AG" ]
alg-geom/9612007
Donu Arapura
Donu Arapura and Pramathanath Sastry
Intermediate Jacobians of moduli spaces
AMS-LaTeX, 16 pages
null
null
null
null
Let $SU_X(n,L)$ be the moduli space of rank n semistable vector bundles with fixed determinant L on a smooth projective genus g curve X. Let $SU_X^s(n,L)$ denote the open subset parametrizing stable bundles. We show that if g>3 and n > 1, then the mixed Hodge structure on $H^3(SU_X^s(n, L))$ is pure of type ${(1,2),(...
[ { "version": "v1", "created": "Sat, 7 Dec 1996 20:09:24 GMT" } ]
2008-02-03T00:00:00
[ [ "Arapura", "Donu", "" ], [ "Sastry", "Pramathanath", "" ] ]
alg-geom
\section{Introduction}\label{s:intro} We work throughout over the complex numbers ${\Bbb C}$, i.e. all schemes are over ${\Bbb C}$ and all maps of schemes are maps of ${\Bbb C}$-schemes. A curve, unless otherwise stated, is a smooth complete curve. Points mean geometric points. We will, as is usual in such situations, ...
1996-12-11T08:32:54
9612
alg-geom/9612008
en
https://arxiv.org/abs/alg-geom/9612008
[ "alg-geom", "math.AG" ]
alg-geom/9612008
Jim Bryan
Jim Bryan and Marc Sanders
Instantons on $S^{4}$ and $\cpbar $, rank stabilization, and Bott periodicity
20 pages, keywords: instantons, holomorphic bundles, Bott periodicity LaTeX2e
null
null
null
null
We study the large rank limit of the moduli spaces of framed bundles on the projective plane and the blown-up projective plane. These moduli spaces are identified with various instanton moduli spaces on the 4-sphere and $\cpbar $, the projective plane with the reverse orientation. We show that in the direct limit top...
[ { "version": "v1", "created": "Wed, 11 Dec 1996 07:35:54 GMT" } ]
2008-02-03T00:00:00
[ [ "Bryan", "Jim", "" ], [ "Sanders", "Marc", "" ] ]
alg-geom
\section{Introduction} Let $\M{k}{G_{n}}(X)$ denote the space of (based) $G_{n}$-instantons on $X$ where $G_{n}$ is $SU(n)$, $SO(n)$, or $Sp(n/2)$. In 1989, Taubes \cite{Tau-stable} showed that there is a ``gluing'' map $\M{k}{G_{n}}(X)\hookrightarrow \M{k'}{G_{n}}(X)$ when $k'>k$. He proved that in the direct limit t...
1996-12-13T20:19:36
9612
alg-geom/9612012
en
https://arxiv.org/abs/alg-geom/9612012
[ "alg-geom", "hep-th", "math.AG" ]
alg-geom/9612012
Rolf Schimmrigk
Rolf Schimmrigk
Scaling Behavior on the Space of Calabi-Yau Manifolds
11 pages, 4 eps figs Latex
null
null
BONN-TH-96-13
null
Recent work is reviewed which suggests that certain universal quantities, defined for all Calabi-Yau manifolds, exhibit a specific behavior which is not present for general K\"ahler manifolds. The variables in question, natural from a mathematical perspective, are of physical importance because they determine aspects...
[ { "version": "v1", "created": "Thu, 12 Dec 1996 16:46:01 GMT" }, { "version": "v2", "created": "Fri, 13 Dec 1996 19:18:59 GMT" } ]
2008-02-03T00:00:00
[ [ "Schimmrigk", "Rolf", "" ] ]
alg-geom
\section*{Acknowledgment} It is a pleasure to thank Philip Candelas, Dimitrios Dais, Xenia de la Ossa, Ed Derrick, Michael Flohr, Ariane Frey, Jerry Hinnefeld, Vadim Kaplunovsky, Jack Morse, Werner Nahm, Steve Shore, and especially Andreas Honecker, Monika Lynker and Katrin Wendland for discussions. I'm grateful to the...
1997-04-23T16:37:10
9612
alg-geom/9612016
en
https://arxiv.org/abs/alg-geom/9612016
[ "alg-geom", "math.AG" ]
alg-geom/9612016
Dmitry Kaledin
D. Kaledin
Integrability of the twistor space for a hypercomplex manifold
9 pages, Latex2e
null
null
null
null
A hypercomplex manifold is by definition a smooth manifold equipped with two anticommuting integrable almost complex structures. For example, every hyperkaehler manifold is canonically hypercomplex (the converse is not true). For every hypercomplex manifold M, the two almost complex structures define a smooth action ...
[ { "version": "v1", "created": "Wed, 18 Dec 1996 20:14:58 GMT" } ]
2008-02-03T00:00:00
[ [ "Kaledin", "D.", "" ] ]
alg-geom
\section*{Introduction} A {\em hyperk\"ahler manifold} is by definition a Riemannian manifold eqipped with a smooth parallel action of the algebra of quaternions on its tangent bundle. Hyperk\"ahler manifolds were introduced by Calabi in \cite{C} and have since been the subject of much research. They have been shown ...
1998-01-19T10:34:51
9612
alg-geom/9612011
en
https://arxiv.org/abs/alg-geom/9612011
[ "alg-geom", "math.AG" ]
alg-geom/9612011
null
Atsushi Moriwaki
Relative Bogomolov's inequality and the cone of positive divisors on the moduli space of stable curves
Version 4.5 (33 pages). This paper will appear in Journal of AMS
null
null
null
null
Let f : X --> Y be a projective morphism of smooth algebraic varieties over an algebraically closed field of characteristic zero with dim f = 1. Let E be a vector bundle of rank r on X. In this paper, we would like to show that if X_y is smooth and E_y is semistable for some point y of Y, then f_* (2r c_2(E) - (r-1) ...
[ { "version": "v1", "created": "Thu, 12 Dec 1996 14:48:28 GMT" }, { "version": "v2", "created": "Fri, 3 Jan 1997 14:01:48 GMT" }, { "version": "v3", "created": "Thu, 30 Jan 1997 15:18:32 GMT" }, { "version": "v4", "created": "Mon, 7 Apr 1997 06:07:32 GMT" }, { "ver...
2008-02-03T00:00:00
[ [ "Moriwaki", "Atsushi", "" ] ]
alg-geom
\section*{Introduction} \renewcommand{\theTheorem}{\Alph{Theorem}} Throughout this paper, we fix an algebraically closed field $k$. Let $f : X \to Y$ be a surjective and projective morphism of quasi-projective varieties over $k$ with $\dim f = 1$. Let $E$ be a vector bundle of rank $r$ on $X$. Then, we define the {\em...
1998-03-12T14:07:15
9612
alg-geom/9612010
en
https://arxiv.org/abs/alg-geom/9612010
[ "alg-geom", "math.AG" ]
alg-geom/9612010
Wolfgang Ebeling
Wolfgang Ebeling
Strange duality, mirror symmetry, and the Leech lattice
LaTeX2e, 21 p. with 4 fig.; some corrections and additions
null
null
University of Hannover Preprint No. 279
null
We give a survey on old and new results concerning Arnold's strange duality. We show that most of the features of this duality continue to hold for the extension of it discovered by C. T. C. Wall and the author. The results include relations to mirror symmetry and the Leech lattice.
[ { "version": "v1", "created": "Thu, 12 Dec 1996 14:21:16 GMT" }, { "version": "v2", "created": "Thu, 12 Mar 1998 13:07:11 GMT" } ]
2008-02-03T00:00:00
[ [ "Ebeling", "Wolfgang", "" ] ]
alg-geom
\section*{Introduction} More than 20 years ago, V.~I.~Arnold \cite{Arnold75} discovered a strange duality among the 14 exceptional unimodal hypersurface singularities. A beautiful interpretation of this duality was given by H.~Pinkham \cite{Pinkham77} and independently by I.~V.~Dolgachev and V.~V.~Nikulin \cite{DN77, ...
1996-12-06T15:28:42
9612
alg-geom/9612005
en
https://arxiv.org/abs/alg-geom/9612005
[ "alg-geom", "math.AG" ]
alg-geom/9612005
Ezra Getzler
Ezra Getzler
The semi-classical approximation for modular operads
11 pages, amslatex-1.2
null
null
MPI 96-145
null
The semi-classical approximation is an explicit formula of mathematical physics for the sum of Feynman diagrams with a single circuit.In this paper, we study the same problem in the setting of modular operads (see dg-ga/9408003); instead of being a number, the interaction at a vertex of valence n is an S_n-module. ...
[ { "version": "v1", "created": "Fri, 6 Dec 1996 14:28:42 GMT" } ]
2008-02-03T00:00:00
[ [ "Getzler", "Ezra", "" ] ]
alg-geom
\subsection*{Acknowledgments} I wish to thank the Department of Mathematics at the Universit\'e de Paris-VII the Max-Planck-Institut f\"ur Mathematik in Bonn for their hospitality during the inception and completion, respectively, of this paper. I am grateful to D. Zagier for showing me the asymptotic expansion of Cor...
1997-09-04T21:14:16
9709
alg-geom/9709004
en
https://arxiv.org/abs/alg-geom/9709004
[ "alg-geom", "math.AG" ]
alg-geom/9709004
Ravi Vakil
Ravi Vakil
Genus g Gromov-Witten invariants of Del Pezzo surfaces: Counting plane curves with fixed multiple points
LaTeX2e
null
null
null
null
As another application of the degeneration methods of [V3], we count the number of irreducible degree $d$ geometric genus $g$ plane curves, with fixed multiple points on a conic $E$, not containing $E$, through an appropriate number of general points in the plane. As a special case, we count the number of irreducible...
[ { "version": "v1", "created": "Thu, 4 Sep 1997 19:13:49 GMT" } ]
2008-02-03T00:00:00
[ [ "Vakil", "Ravi", "" ] ]
alg-geom
\section{Introduction} In this note, we count the number of irreducible degree $d$ geometric genus $g$ plane curves, with fixed multiple points on a conic $E$, not containing $E$, through an appropriate number of general points in the plane. As a special case, we count the number of irreducible genus $g$ curves in an...
1997-09-17T18:48:54
9709
alg-geom/9709020
en
https://arxiv.org/abs/alg-geom/9709020
[ "alg-geom", "math.AG" ]
alg-geom/9709020
Vladimir Masek
Vladimir Masek (Washington Univ. in St. Louis)
Very ampleness of adjoint linear systems on smooth surfaces with boundary
22 pages, AMS-LaTeX 1.2
null
null
null
null
Let M be a Q-divisor on a smooth surface over C. In this paper we give criteria for very ampleness of the adjoint of the round-up of M. (Similar results for global generation were given by Ein and Lazarsfeld and used in their proof of Fujita's Conjecture in dimension 3.) In the last section we discuss an example whic...
[ { "version": "v1", "created": "Wed, 17 Sep 1997 16:48:39 GMT" } ]
2016-08-30T00:00:00
[ [ "Masek", "Vladimir", "", "Washington Univ. in St. Louis" ] ]
alg-geom
\subsection*{Contents} \begin{enumerate} \item[0.] Introduction \item[1.] Base-point-freeness \item[2.] Separation of points \item[3.] Separation of tangent directions \item[4.] Example \end{enumerate} \subsection*{Notations} \begin{tabbing} 99\=9999999999\=9999999999999999999999999999\kill \>$\lceil \c...
1997-09-04T21:13:34
9709
alg-geom/9709003
en
https://arxiv.org/abs/alg-geom/9709003
[ "alg-geom", "math.AG" ]
alg-geom/9709003
Ravi Vakil
Ravi Vakil
Counting curves of any genus on rational ruled surfaces
LaTeX2e
null
null
null
null
In this paper we study the geometry of the Severi varieties parametrizing curves on the rational ruled surface $\fn$. We compute the number of such curves through the appropriate number of fixed general points on $\fn$, and the number of such curves which are irreducible. These numbers are known as Severi degrees; th...
[ { "version": "v1", "created": "Thu, 4 Sep 1997 19:13:10 GMT" } ]
2008-02-03T00:00:00
[ [ "Vakil", "Ravi", "" ] ]
alg-geom
\section{Introduction} In this paper we study the geometry of the {\em Severi varieties} parametrizing curves on the rational ruled surface ${\mathbb F}_n = \mathbb P ({\mathcal{O}}_{\mathbb P^1} \oplus {\mathcal{O}}_{\mathbb P^1}(n))$ ($n \ge 0$) in a given divisor class. We compute the number of such curves through...
1997-09-11T11:44:37
9709
alg-geom/9709014
fr
https://arxiv.org/abs/alg-geom/9709014
[ "alg-geom", "math.AG" ]
alg-geom/9709014
Jean-Marc Drezet
Jean-Marc Dr\'ezet
Fibr\'es prioritaires g\'en\'eriques instables sur le plan projectif
LaTeX
null
null
null
null
The structure of the generic prioritary sheaf on the projective plane is given, when it cannot be semi-stable
[ { "version": "v1", "created": "Thu, 11 Sep 1997 09:42:14 GMT" } ]
2008-02-03T00:00:00
[ [ "Drézet", "Jean-Marc", "" ] ]
alg-geom
\section{Introduction} Les faisceaux prioritaires sur \proj{2} ont \'et\'e introduits par A. Hirschowitz et Y. Laszlo dans \cite{hi_la}. Rappelons qu'un faisceau coh\'erent ${\cal E}$ sur \proj{2} est dit {\em prioritaire} s'il est sans torsion et si \ \m{\mathop{\rm Ext}\nolimits^2({\cal E},{\cal E}(-1))=0}. Par exem...
1997-09-26T22:13:44
9709
alg-geom/9709030
en
https://arxiv.org/abs/alg-geom/9709030
[ "alg-geom", "math.AG" ]
alg-geom/9709030
Brent Gordon
B. Brent Gordon
A Survey of the Hodge Conjecture for Abelian Varieties
68 pages, AMSTeX. To appear as Appendix B in the upcoming second edition of "A Survey of the Hodge Conjecture" by James D. Lewis
null
null
null
null
We review what is known about the Hodge conjecture for abelian varieties, with some emphasis on how Mumford-Tate groups have been applied to this problem.
[ { "version": "v1", "created": "Fri, 26 Sep 1997 20:13:44 GMT" } ]
2008-02-03T00:00:00
[ [ "Gordon", "B. Brent", "" ] ]
alg-geom
\chapter{\let\savedef@\chapter \def\chapter##1{\let\chapter\savedef@ \leavevmode\hskip-\leftskip \rlap{\vbox to\z@{\vss\centerline{\tenpoint \frills@{CHAPTER\space\afterassignment\chapterno@ \global\chaptercount@=}% ##1\unskip}\baselineskip36pt\null}}\hskip\leftskip}% \nofrillscheck\chapter} \de...
1997-09-11T17:31:29
9709
alg-geom/9709011
en
https://arxiv.org/abs/alg-geom/9709011
[ "alg-geom", "math.AG" ]
alg-geom/9709011
Jonathan Fine
Jonathan Fine
Local-global intersection homology
LaTeX 2e. 28 pages. This paper defines new intersection homology groups, that provide important new information
null
null
null
null
This paper defines new intersection homology groups. The basic idea is this. Ordinary homology is locally trivial. Intersection homology is not. It may have significant local cycles. A local-global cycle is defined to be a family of such local cycles that is, at the same time, a global cycle. The motivating problem i...
[ { "version": "v1", "created": "Wed, 10 Sep 1997 14:58:41 GMT" }, { "version": "v2", "created": "Thu, 11 Sep 1997 15:31:29 GMT" } ]
2008-02-03T00:00:00
[ [ "Fine", "Jonathan", "" ] ]
alg-geom
\section{Introduction} This paper defines new intersection homology groups. They record, in a global way, local information about the singularities. They give rise to new information, both globally and locally, and vanish on nonsingular varieties. Such groups are required, to obtain a satisfactory understanding of g...
1997-09-12T23:10:33
9709
alg-geom/9709016
en
https://arxiv.org/abs/alg-geom/9709016
[ "alg-geom", "math.AG" ]
alg-geom/9709016
James A. Carlson
Daniel Allcock, James A. Carlson, Domingo Toledo
A Complex Hyperbolic Structure for Moduli of Cubic Surfaces
Six pages, plain tex, available at http://www.math.utah.edu/~allcock
null
10.1016/S0764-4442(97)82711-5
null
null
We show that the moduli space M of marked cubic surfaces is biholomorphic to the quotient by a discrete group generated by complex reflections of the complex four-ball minus the reflection hyperplanes of the group. Thus M carries a complex hyperbolic structure: an (incomplete) metric of constant holomorphic sectional...
[ { "version": "v1", "created": "Fri, 12 Sep 1997 21:10:31 GMT" } ]
2009-10-30T00:00:00
[ [ "Allcock", "Daniel", "" ], [ "Carlson", "James A.", "" ], [ "Toledo", "Domingo", "" ] ]
alg-geom
\section{1. Main results} To a (marked) cubic surface corresponds a (marked) cubic threefold defined as the triple cover of ${\Bbb P}^3$ ramified along the surface. The period map $f$ for these threefolds is defined on the moduli space $M$ of marked cubic surfaces and takes its values in the quotient of the unit bal...
1997-09-10T21:18:41
9709
alg-geom/9709013
en
https://arxiv.org/abs/alg-geom/9709013
[ "alg-geom", "math.AG" ]
alg-geom/9709013
Fernando Torres
Rainer Fuhrmann, Fernando Torres
On Weierstrass points and optimal curves
22 pages, Latex 2e
Rend. Circ. Mat. Palermo Suppl. 51, (1998) 25--46
null
null
null
We use Weierstrass Point Theory and Frobenius orders to prove the uniqueness (up to isomorphism) of some optimal curves.
[ { "version": "v1", "created": "Wed, 10 Sep 1997 19:18:20 GMT" } ]
2008-02-03T00:00:00
[ [ "Fuhrmann", "Rainer", "" ], [ "Torres", "Fernando", "" ] ]
alg-geom
\section{Preliminaries}\label{1} In this section we summarize some background material concerning Weierstrass Point Theory, Frobenius orders and a rational divisor arising from the Zeta Function of a curve defined over a finite field. \subsection{Weierstrass Point Theory}\label{1.1} Here we repeat relevant material f...
1997-09-02T15:27:01
9709
alg-geom/9709001
en
https://arxiv.org/abs/alg-geom/9709001
[ "alg-geom", "math.AG" ]
alg-geom/9709001
Mikhail Zaidenberg
H. Flenner and M. Zaidenberg
Rational cuspidal plane curves of type (d, d-3)
17 Pages. Latex
null
null
null
null
In the previous paper [E-print alg-geom/9507004] we classified the rational cuspidal plane curves C with a cusp of multiplicity deg C - 2. In particular, we showed that any such curve can be transformed into a line by Cremona transformations. Here we do the same for the rational cuspidal plane curves C with a cusp of...
[ { "version": "v1", "created": "Mon, 1 Sep 1997 19:10:44 GMT" }, { "version": "v2", "created": "Tue, 2 Sep 1997 13:29:03 GMT" } ]
2008-02-03T00:00:00
[ [ "Flenner", "H.", "" ], [ "Zaidenberg", "M.", "" ] ]
alg-geom
\section*{Introduction} Let $C \subset {\bf P}^2$ be a rational cuspidal curve; that is, it has only irreducible singularities (called {\it cusps}). We say that $C$ is of type $(d,\,m)$ if $d =$deg$\,C$ is the degree and $m = \max_{P \in {\rm Sing}\,C} \{$mult$_P C\}$ is the maximal multiplicity of the singular points...
1997-09-30T07:13:24
9709
alg-geom/9709033
en
https://arxiv.org/abs/alg-geom/9709033
[ "alg-geom", "math.AG" ]
alg-geom/9709033
Daisuke Matsushita
Daisuke Matsushita
On fibre space structures of a projective irreducible symplectic manifold
null
null
null
null
null
In this note, we investigate fibre space structures of a projective irreducible symplectic manifold. We prove that an 2n-dimensional projective irreducible symplectic manifold admits only an n-dimensional fibration over a Fano variety which has only Q-factorial log-terminal singularities and whose Picard number is on...
[ { "version": "v1", "created": "Tue, 30 Sep 1997 05:13:24 GMT" } ]
2016-08-30T00:00:00
[ [ "Matsushita", "Daisuke", "" ] ]
alg-geom
\section{Introduction} We first define an {\it irreducible symplectic manifold}. \begin{defn} A complex manifold $X$ is called {\it irreducible symplectic} if $X$ satisfies the following three conditions: \begin{enumerate} \item $X$ is compact and K\"{a}hler. \item $X$ is simply connected. \item $H^{0}(X,\Omega^{...
1997-09-25T09:48:39
9709
alg-geom/9709027
en
https://arxiv.org/abs/alg-geom/9709027
[ "alg-geom", "math.AG" ]
alg-geom/9709027
Masahiko Saito
Shinobu Hosono, Masa-Hiko Saito, and Jan Stienstra
On Mirror Symmetry Conjecture for Schoen's Calabi-Yau 3 folds
LaTeX Version 2.09, 36 pages. Submitted to The Proceedings of Taniguchi Symposium 1997, "Integrable Systems and Algebraic Geometry, Kobe/Kyoto"
null
null
null
null
In this paper, we verify a part of the Mirror Symmetry Conjecture for Schoen's Calabi-Yau 3-fold, which is a special complete intersection in a toric variety. We calculate a part of the prepotential of the A-model Yukawa couplings of the Calabi-Yau 3-fold directly by means of a theta function and Dedekind's eta funct...
[ { "version": "v1", "created": "Thu, 25 Sep 1997 07:48:37 GMT" } ]
2008-02-03T00:00:00
[ [ "Hosono", "Shinobu", "" ], [ "Saito", "Masa-Hiko", "" ], [ "Stienstra", "Jan", "" ] ]
alg-geom
\section{Introduction} \label{intro} Let $W$ be a generic complete intersection variety in $\P1 \times \P2 \times \P2$ which is defined by two equations of multi-degrees $(1, 3, 0)$ and $(1, 0, 3)$ respectively. A generic $W$ is a non-singular Calabi-Yau 3-fold, which we call {\em Schoen's Calabi-Yau 3-fold}~\cit...
1997-09-17T17:52:07
9709
alg-geom/9709019
en
https://arxiv.org/abs/alg-geom/9709019
[ "alg-geom", "math.AG" ]
alg-geom/9709019
Vladimir Masek
Vladimir Masek (Washington Univ. in St. Louis)
Kawachi's invariant for normal surface singularities
16 pages, AMS-LaTeX 1.2
null
null
null
null
We study a useful numerical invariant of normal surface singularities, introduced recently by T. Kawachi. Using this invariant, we give a quick proof of the (well-known) fact that all log-canonical surface singularities are either elliptic Gorenstein or rational (without assuming a priori that they are Q-Gorenstein)....
[ { "version": "v1", "created": "Wed, 17 Sep 1997 15:51:59 GMT" } ]
2008-02-03T00:00:00
[ [ "Masek", "Vladimir", "", "Washington Univ. in St. Louis" ] ]
alg-geom
\subsection*{Contents} \begin{enumerate} \item[0.] Introduction \item[1.] Kawachi's invariant and log-canonical singularities \item[2.] A theorem of Reider type on normal surfaces with boundary \end{enumerate} \subsection*{Notations} \begin{tabbing} 99\=9999999999\=9999999999999999999999999999\kill \>$\lcei...
1997-09-29T10:42:46
9709
alg-geom/9709031
en
https://arxiv.org/abs/alg-geom/9709031
[ "alg-geom", "math.AG" ]
alg-geom/9709031
Wolf Barth
W. Barth
K3 Surfaces with Nine Cusps
LaTeX
null
null
null
null
By a K3-surface with nine cusps I mean a surface with nine isolated double points A_2, but otherwise smooth, such that its minimal desingularisation is a K3-surface. It is shown, that such a surface admits a cyclic triple cover branched precisely over the cusps. This parallels the theorem of Nikulin, that a K3-surfac...
[ { "version": "v1", "created": "Mon, 29 Sep 1997 08:42:46 GMT" } ]
2008-02-03T00:00:00
[ [ "Barth", "W.", "" ] ]
alg-geom
\section{Introduction} If $E_1,...,E_{16}$ are 16 disjoint, smooth curves on a $K3$-surface $X$ then the divisor $\sum_1^{16} E_i$ is divisible by $2$ in $Pic(X)$. This was observed by V.V. Nikulin [N]. Equivalently: If $\bar{X}$ is the surface obtained from $X$ by blowing down the 16 rational curves to nodes $e_i \in...
1997-09-15T22:55:44
9709
alg-geom/9709017
en
https://arxiv.org/abs/alg-geom/9709017
[ "alg-geom", "math.AG" ]
alg-geom/9709017
Yavor Markov
Y. Markov, V. Tarasov, A. Varchenko
The Determinant of a Hypergeometric Period Matrix
21 pages, no figures, LaTeX2e
null
null
null
null
We consider a function $U=e^{-f_0}\prod_j^N f_j^{\alpha_j}$ on a real affine space, here $f_0,..,f_N$ are linear functions, $\alpha_1, ...,\alpha_N$ complex numbers. The zeros of the functions $f_1, ..., f_N$ form an arrangement of hyperplanes in the affine space. We study the period matrix of the hypergeometric inte...
[ { "version": "v1", "created": "Mon, 15 Sep 1997 20:51:53 GMT" } ]
2008-02-03T00:00:00
[ [ "Markov", "Y.", "" ], [ "Tarasov", "V.", "" ], [ "Varchenko", "A.", "" ] ]
alg-geom
\section{Introduction} The Euler beta function is an alternating product of Euler gamma functions, \begin{equation}\label{2} B (\alpha, \beta)\,=\, {\Gamma (\alpha)\,\Gamma (\beta) \over \Gamma (\alpha + \beta)} \end{equation} where the Euler gamma and beta functions are defined by \begin{equation}\label{1} \Gamma (...
1997-09-10T17:43:13
9709
alg-geom/9709012
en
https://arxiv.org/abs/alg-geom/9709012
[ "alg-geom", "math.AG" ]
alg-geom/9709012
Richard Earl
Richard Earl and Frances Kirwan
The Pontryagin rings of moduli spaces of arbitrary rank holomorphic bundles over a Riemann surface
AMS-Latex, 15 pages, no figures
null
null
null
null
The cohomology of the moduli spaces of stable bundles M(n,d), of coprime rank n and degree d, over a Riemann surface (of genus g > 1) have been intensely studied over the past three decades. We prove in this paper that the Pontryagin ring of M(n,d) vanishes in degrees above 2n(n-1)(g-1) and that this bound is strict ...
[ { "version": "v1", "created": "Wed, 10 Sep 1997 15:42:31 GMT" } ]
2008-02-03T00:00:00
[ [ "Earl", "Richard", "" ], [ "Kirwan", "Frances", "" ] ]
alg-geom
\section{Introduction} The cohomology of ${\cal M}(n,d)$, the moduli space of stable holomorphic bundles of coprime rank $n$ and degree $d$ and fixed determinant, over a Riemann surface $\Sigma$ of genus $g \geq 2$, has been widely studied and from a wide range of approaches. Narasimhan and Seshadri \cite{NS} original...
1997-09-30T15:36:07
9709
alg-geom/9709034
en
https://arxiv.org/abs/alg-geom/9709034
[ "alg-geom", "math.AG", "math.CO" ]
alg-geom/9709034
Frank Sottile
Nantel Bergeron (York University, Toronto) and Frank Sottile (University of Toronto)
Skew Schubert functions and the Pieri formula for flag manifolds
24 pages, LaTeX 2e, with epsf.sty
Trans. Amer. Math. Soc., 354 No. 2, (2002), 651-673
10.1090/S0002-9947-01-02845-8
MSRI 1997-096
null
We show the equivalence of the Pieri formula for flag manifolds and certain identities among the structure constants, giving new proofs of both the Pieri formula and of these identities. A key step is the association of a symmetric function to a finite poset with labeled Hasse diagram satisfying a symmetry condition....
[ { "version": "v1", "created": "Tue, 30 Sep 1997 13:35:57 GMT" } ]
2016-11-08T00:00:00
[ [ "Bergeron", "Nantel", "", "York University, Toronto" ], [ "Sottile", "Frank", "", "University of Toronto" ] ]
alg-geom
\section*{Introduction} A fundamental open problem in the theory of Schubert polynomials is to find an analog of the Littlewood-Richardson rule. By this, we mean a bijective description of the structure constants for the ring of polynomials with respect to its basis of Schubert polynomials. Such a rule would express t...
1997-09-09T21:32:23
9709
alg-geom/9709010
en
https://arxiv.org/abs/alg-geom/9709010
[ "alg-geom", "math.AG" ]
alg-geom/9709010
Yuri Tschinkel
Matthias Strauch and Yuri Tschinkel
Height zeta functions of toric bundles over flag varieties
64 pages, LaTeX
null
null
null
null
We investigate analytic properties of height zeta functions of toric bundles over flag varieties.
[ { "version": "v1", "created": "Tue, 9 Sep 1997 19:29:16 GMT" } ]
2008-02-03T00:00:00
[ [ "Strauch", "Matthias", "" ], [ "Tschinkel", "Yuri", "" ] ]
alg-geom
\section{Introduction} \label{1} \subsection* \noindent {\bf 1.1}\hskip 0,5cm Let $X$ be a nonsingular projective algebraic variety over a number field $F$. Let ${\cal L}=\left(L, (\|\cdot\|_v)_v\right)$ be a metrized line bundle on $X$, i.e., a line bundle $L$ together with a family of $v$-adic metrics, where $...
1997-09-16T21:14:56
9709
alg-geom/9709018
en
https://arxiv.org/abs/alg-geom/9709018
[ "alg-geom", "math.AG" ]
alg-geom/9709018
Lakshmibai
V. Lakshmibai and Peter Magyar
Degeneracy Schemes and Schubert Varieties
16 pp, Northeastern University, Latex
null
null
null
null
A result of Zelevinsky states that an orbit closure in the space of representations of the equioriented quiver of type $A_h$ is in bijection with the opposite cell in a Schubert variety of a partial flag variety $SL(n)/Q$. We prove that Zelevinsky's bijection is a scheme-theoretic isomorphism, which shows that the un...
[ { "version": "v1", "created": "Tue, 16 Sep 1997 19:16:12 GMT" } ]
2008-02-03T00:00:00
[ [ "Lakshmibai", "V.", "" ], [ "Magyar", "Peter", "" ] ]
alg-geom
\section{Zelevinsky's bijection} \subsection{Quiver varieties} Fix an $h$-tuple of non-negative integers ${\bf n} = (n_1,\ldots,n_h)$ and a list of vector spaces $V_1,\ldots, V_h$ over an arbitrary field ${\bf k}$ with respective dimensions $n_1,\ldots,n_h$. Define the {\it variety of quiver representations} (of dime...
1997-09-29T19:35:02
9709
alg-geom/9709032
fr
https://arxiv.org/abs/alg-geom/9709032
[ "alg-geom", "math.AG" ]
alg-geom/9709032
Laurent Evain
L. Evain
Dimension of linear systems: a combinatorial and differential approach
17 pages, in french, also available at http://193.49.162.129/~evain/home.html
null
null
UA 45
null
We give upper-bounds for the dimension of some linear systems. The theorem improves the differential Horace method introduced by Alexander-Hirschowitz, and was conjectured by Simpson. Possible applications are the calculus of the dimension of linear systems of hypersurfaces in a projective space $\PP^n$ with generica...
[ { "version": "v1", "created": "Mon, 29 Sep 1997 17:35:02 GMT" } ]
2008-02-03T00:00:00
[ [ "Evain", "L.", "" ] ]
alg-geom
\section{Introduction par un exemple} Consid\'erons le syst\`eme lin\'eaire ${\cal L}_t$ des courbes projectives planes de degr\'e $d$ passant par trois points fixes $p_1,p_2,p_3$ et par un point $p_4(t)$ avec multiplicit\'es respectives $m_1,m_2,m_3$ et $m_4$. Supposons que $p_1,p_2,p_3$ soient align\'es sur une...
1997-09-25T16:01:03
9709
alg-geom/9709028
en
https://arxiv.org/abs/alg-geom/9709028
[ "alg-geom", "math.AG" ]
alg-geom/9709028
Karin Smith
Edward Bierstone and Pierre D. Milman (University of Toronto)
Resolution of Singularities
45 pages, 7 Postscript figures, LATEX. To appear in Current Developments in Several Complex Variables, MSRI Proceedings, ed. M. Schneider and Y.-T. Siu, Cambridge University Press
null
null
null
null
This article is an exposition of an elementary constructive proof of canonical resolution of singularities in characteristic zero, presented in detail in Invent. Math. 128 (1997), 207-302. We define a new local invariant and get an algorithm for canonical desingularization by successively blowing up its maximum loci....
[ { "version": "v1", "created": "Thu, 25 Sep 1997 14:00:53 GMT" } ]
2008-02-03T00:00:00
[ [ "Bierstone", "Edward", "", "University of Toronto" ], [ "Milman", "Pierre D.", "", "University of Toronto" ] ]
alg-geom
\section{Introduction} Resolution of singularities has a long history that goes back to Newton in the case of plane curves. For higher-dimensional singular spaces, the problem was formulated toward the end of the last century, and it was solved in general, for algebraic varieties defined over fields of characteristic ...
1997-09-06T00:33:58
9709
alg-geom/9709007
en
https://arxiv.org/abs/alg-geom/9709007
[ "alg-geom", "math.AG" ]
alg-geom/9709007
Ravi Vakil
Ravi Vakil
The enumerative geometry of rational and elliptic curves in projective space
LaTeX2e, 95 pages with 18 figures
null
null
null
null
We study the geometry of varieties parametrizing degree d rational and elliptic curves in P^n intersecting fixed general linear spaces and tangent to a fixed hyperplane H with fixed multiplicities along fixed general linear subspaces of H. As an application, we derive recursive formulas for the number of such curves ...
[ { "version": "v1", "created": "Fri, 5 Sep 1997 22:32:50 GMT" } ]
2008-02-03T00:00:00
[ [ "Vakil", "Ravi", "" ] ]
alg-geom
\section{Introduction} \label{intro} In this article, we study the geometry of varieties (over $\mathbb{C}$) parametrizing degree $d$ rational and elliptic curves in $\mathbb P^n$ intersecting fixed general linear spaces and tangent to a fixed hyperplane $H$ with fixed multiplicities along fixed general...
1997-09-04T10:37:48
9709
alg-geom/9709002
en
https://arxiv.org/abs/alg-geom/9709002
[ "alg-geom", "math.AG" ]
alg-geom/9709002
Vicente Munoz Velazquez
Vicente Mu\~noz
Wall-crossing formulae for algebraic surfaces with $q>0$
Latex2e, 20 pages
null
null
null
null
We extend the ideas of Friedman and Qin (Flips of moduli spaces and transition formulae for Donaldson polynomial invariants of rational surfaces) to find the wall-crossing formulae for the Donaldson invariants of algebraic surfaces with geometrical genus zero, positive irregularity and anticanonical divisor effective...
[ { "version": "v1", "created": "Thu, 4 Sep 1997 09:38:04 GMT" } ]
2008-02-03T00:00:00
[ [ "Muñoz", "Vicente", "" ] ]
alg-geom
\section{Introduction} \label{sec:intro} The Donaldson invariants of a smooth oriented $4$-manifold $X$ depend by definition on a Riemannian metric $g$. In the case $b^+>1$ they however turn out to be independent of $g$. When $b^+=1$, they depend on $g$ through a structure of walls and chambers, that we recall brief...
1997-09-26T19:11:48
9709
alg-geom/9709029
en
https://arxiv.org/abs/alg-geom/9709029
[ "alg-geom", "hep-th", "math.AG" ]
alg-geom/9709029
Robert Friedman
Robert Friedman, John W. Morgan, and Edward Witten
Vector Bundles over Elliptic Fibrations
101 pages, AMS-TeX, amsppt style
null
null
null
null
This paper gives various methods for constructing vector bundles over elliptic curves and more generally over families of elliptic curves. We construct universal families over generalized elliptic curves via spectral cover methods and also by extensions, and then give a relative version of the construction in familie...
[ { "version": "v1", "created": "Fri, 26 Sep 1997 17:11:47 GMT" } ]
2008-02-03T00:00:00
[ [ "Friedman", "Robert", "" ], [ "Morgan", "John W.", "" ], [ "Witten", "Edward", "" ] ]
alg-geom
\section{Introduction} Let $\pi \: Z \to B$ be an elliptic fibration with a section. The goal of this paper is to study holomorphic vector bundles over $Z$. We are mainly concerned with vector bundles $V$ with trivial determinant, or more generally such that $\det V$ has trivial restriction to each fiber, so that $\d...
1998-12-11T18:24:46
9709
alg-geom/9709025
en
https://arxiv.org/abs/alg-geom/9709025
[ "alg-geom", "math.AG" ]
alg-geom/9709025
Christoph Sorger
Christoph Sorger
On Moduli of G-bundles over Curves for exceptional G
Plain TeX, 6 p. Reason for resubmission: proof of main result has been simplified
null
null
null
null
Let $G$ be a simple and simply connected complex Lie group, ${\goth{g}}$ its Lie algebra. I remove the restriction ``$G$ is of classical type or $G_2$'' made on $G$ in the papers of Beauville, Laszlo and myself [L-S] and [B-L-S] on the moduli of principal G-bundles over a curve. As I will just "patch" the missing tec...
[ { "version": "v1", "created": "Mon, 22 Sep 1997 20:56:23 GMT" }, { "version": "v2", "created": "Thu, 2 Oct 1997 09:18:16 GMT" } ]
2009-09-25T00:00:00
[ [ "Sorger", "Christoph", "" ] ]
alg-geom
\section{Introduction} \par\hskip 1truecm\relax Let $G$ be a simple and simply connected complex Lie group, $\g$ its Lie algebra. In the following, I remove the restriction ``$G$ is of classical type or $G_2$'' made on $G$ in the papers of Beauville, Laszlo and myself \cite{L-S:verlinde},\cite{B-L-S:picard} on the mod...
1994-08-24T22:26:05
9408
alg-geom/9408007
en
https://arxiv.org/abs/alg-geom/9408007
[ "alg-geom", "math.AG" ]
alg-geom/9408007
Caryn Werner
Caryn Werner
A surface of general type with \( p_g =q =0, K^2 =1 \)
13 pages, AMS-LaTex version 1.1
null
null
null
null
We construct a surface of general type with invariants \( \chi = K^2 = 1 \) and torsion group \( \Bbb{Z}/{2} \). We use a double plane construction by finding a plane curve with certain singularities, resolving these, and taking the double cover branched along the resulting smooth curve.
[ { "version": "v1", "created": "Wed, 24 Aug 1994 20:25:38 GMT" } ]
2008-02-03T00:00:00
[ [ "Werner", "Caryn", "" ] ]
alg-geom
\section{Introduction} In this paper we construct a minimal surface \(X\) of general type with \(\rm{{p}_{g}}=0,\rm{q}=0, {K}^{2}=1,\) and \( \operatorname{Tors} X \cong \Bbb{Z}/{2}\). In \cite{Ca}, Campedelli noted that if a degree ten plane curve could be found having certain singularities, a double plane constructio...
1994-08-04T16:05:34
9408
alg-geom/9408001
en
https://arxiv.org/abs/alg-geom/9408001
[ "alg-geom", "math.AG" ]
alg-geom/9408001
Daniel Huybrechts
Lothar Goettsche, Daniel Huybrechts
Hodge numbers of moduli spaces of stable bundles on K3 surfaces
12 pages, latex
null
null
null
null
We show that the Hodge numbers of the moduli space of stable rank two sheaves with primitive determinant on a K3 surface coincide with the Hodge numbers of an appropriate Hilbert scheme of points on the K3 surface. The precise result is: Theorem: Let $X$ be a K3 surface, $L$ a primitive big and nef line bundle and $H...
[ { "version": "v1", "created": "Thu, 4 Aug 1994 15:02:20 GMT" } ]
2008-02-03T00:00:00
[ [ "Goettsche", "Lothar", "" ], [ "Huybrechts", "Daniel", "" ] ]
alg-geom
\section{A special case} In this section we prove the theorem in the case that ${\rm Pic }(X)=\hbox{\sym \char '132}\cdot L$ and $c_2=\frac{L^2}{2}+3$. {\small\subsection{ The birational correspondence to the Hilbert scheme}} Throughout this section we will assume that the Picard group is generated by an ample line bu...
1994-08-09T11:21:15
9408
alg-geom/9408002
en
https://arxiv.org/abs/alg-geom/9408002
[ "alg-geom", "math.AG" ]
alg-geom/9408002
Luca Barbieri-Viale
Luca Barbieri-Viale
${\cal H}$-cohomologies versus algebraic cycles
51 pages, LaTeX 2.09
Math. Nachr. 184 (1997), 5-57
null
null
null
Global intersection theories for smooth algebraic varieties via products in {\it appropriate}\, Poincar\'e duality theories are obtained. We assume given a (twisted) cohomology theory $H^*$ having a cup product structure and we let consider the ${\cal H}$-cohomology functor $X\leadsto H^{\#}_{Zar}(X,{\cal H}^*)$ wher...
[ { "version": "v1", "created": "Mon, 8 Aug 1994 14:29:25 GMT" } ]
2008-02-03T00:00:00
[ [ "Barbieri-Viale", "Luca", "" ] ]
alg-geom
\section{Introduction} After Quillen's proof of the Gersten conjecture (see \cite{Q}), for algebraic regular schemes, a natural approach to the theory of algebraic cycles appears to be by dealing with the ``formalism'' associated to (local) higher $K$-theory, as it is manifestly expressed by the work of Bloch and Gill...
1994-08-24T11:31:56
9408
alg-geom/9408006
en
https://arxiv.org/abs/alg-geom/9408006
[ "alg-geom", "math.AG" ]
alg-geom/9408006
Serge M. L'vovsky
S.L'vovsky
On Landsberg's criterion for complete intersections
4 pages, LaTeX 2.09
null
null
null
null
In his preprint ``Differential-Geometric Characterizations of Complete Intersections'' (alg-geom/9407002), J.M.Landsberg introduces an elementary characterization of complete intersections. The proof of this criterion uses the method of moving frames. The aim of this note is to present an elementary proof of Landsber...
[ { "version": "v1", "created": "Wed, 24 Aug 1994 08:43:07 GMT" } ]
2008-02-03T00:00:00
[ [ "L'vovsky", "S.", "" ] ]
alg-geom
\section*{Introduction} In his preprint~\cite{Lan}, J.M.~Landsberg introduces an elementary characterization of complete intersections (Proposition~1.2 in \cite{Lan}). The proof of this proposition uses the method of moving frames. The aim of this note is to present an elementary proof of Landsberg's criterion that is ...
1994-08-29T10:45:38
9408
alg-geom/9408008
en
https://arxiv.org/abs/alg-geom/9408008
[ "alg-geom", "math.AG" ]
alg-geom/9408008
Robert W. Berger
Robert W. Berger
Various Notions of Associated Prime Ideals
27 pages, AMS-LaTeX 1.1
null
null
null
null
Three notions of associated prime ideals, which are equivalent in the noetherian case but differ in the non notherian case, are discussed. Examples illustrate the scope of the notions.
[ { "version": "v1", "created": "Mon, 29 Aug 1994 08:37:20 GMT" } ]
2008-02-03T00:00:00
[ [ "Berger", "Robert W.", "" ] ]
alg-geom
\section*{Introduction} In the theory of modules over commutative rings there are several possibilities of defining associated prime ideals. The usual definition of an associated prime ideal $\frak p$ for a module $M$ is that $\frak p$ is the annihilator of an element of $M$. In \cite{Bourbaki-Alg-Comm-4} \S 1 exercise...
1993-01-06T16:06:57
9301
alg-geom/9301003
en
https://arxiv.org/abs/alg-geom/9301003
[ "alg-geom", "math.AG" ]
alg-geom/9301003
null
Marc Coppens and Takao Kato
Non-trivial Linear Systems on Smooth Plane Curves
15 pages, LaTeX 2.09
null
null
null
null
Let $C$ be a smooth plane curve of degree $d$ defined over an algebraically closed field $k$. A base point free complete very special linear system $g^r_n$ on $C$ is trivial if there exists an integer $m\ge 0$ and an effective divisor $E$ on $C$ of degree $md-n$ such that $g^r_n=|mg^2_d-E|$ and $r=(m^2+3m)/2-(md-n)$....
[ { "version": "v1", "created": "Wed, 6 Jan 1993 15:15:44 GMT" } ]
2008-02-03T00:00:00
[ [ "Coppens", "Marc", "" ], [ "Kato", "Takao", "" ] ]
alg-geom
\section{Introduction} Let $C$ be a smooth plane curve of degree $d$ defined over an algebraically closed field $k$. In \cite{noether}, while studying space curves, Max Noether considered the following question. For $n\in{\bbb Z}_{\ge 1}$ find $\ell (n)\in{\bbb Z}_{\ge 0}$ such that there exists a linear system $g^{...
1993-02-01T20:50:11
9301
alg-geom/9301006
en
https://arxiv.org/abs/alg-geom/9301006
[ "alg-geom", "hep-th", "math.AG" ]
alg-geom/9301006
null
Sheldon Katz
Rational curves on Calabi-Yau manifolds: verifying predictions of Mirror Symmetry
12 pages, LaTeX (Replaced version corrects an error in the formula for bundle $B'$ on page 5, and changes the order of some entries in tables 2 and 3 for compatibility with the associated computer file)
null
null
OSU Math 1992-3
null
Mirror symmetry, a phenomenon in superstring theory, has recently been used to give tentative calculations of several numbers in algebraic geometry. In this paper, the numbers of lines and conics on various hypersurfaces which satisfy certain incidence properties are calculated, and shown to agree with the numbers pr...
[ { "version": "v1", "created": "Wed, 27 Jan 1993 23:05:22 GMT" }, { "version": "v2", "created": "Mon, 1 Feb 1993 19:39:30 GMT" } ]
2008-02-03T00:00:00
[ [ "Katz", "Sheldon", "" ] ]
alg-geom
\section*{} Recently, mirror symmetry, a phenomenon in superstring theory, has been used to give tentative calculations of several numbers in algebraic geometry \nolinebreak\footnote{See the papers in \cite{yau} for general background on mirror symmetry.}. This yields predictions for the number of rational curves of a...
1993-03-08T22:08:32
9301
alg-geom/9301007
en
https://arxiv.org/abs/alg-geom/9301007
[ "alg-geom", "math.AG" ]
alg-geom/9301007
Zhi-Jie Chen
Zhi-Jie Chen
Bounds of automorphism groups of genus 2 fibrations
30 pages, LaTeX2.09
null
null
null
null
For a complex surface of general type with a relatively minimal genus 2 fibration, the bounds of the orders of the automorphism group of the fibration, of its abelian subgroups and of its cyclic subgroups are determined as linear functions of $c^2_1$. Most of them are the best.
[ { "version": "v1", "created": "Fri, 29 Jan 1993 21:30:56 GMT" }, { "version": "v2", "created": "Mon, 8 Mar 1993 21:07:47 GMT" } ]
2008-02-03T00:00:00
[ [ "Chen", "Zhi-Jie", "" ] ]
alg-geom
\section{Preliminaries} The surfaces with genus 2 pencils have been largely studied by many authors. The facts we needed in this paper mostly appeared in [3, 6, 9, 10]. In particular, Xiao's book \cite{X3} gave a systematic description of the properties of genus 2 fibrations which are just what we needed here. Unfortu...
1993-01-20T12:50:02
9301
alg-geom/9301004
en
https://arxiv.org/abs/alg-geom/9301004
[ "alg-geom", "math.AG" ]
alg-geom/9301004
Sorin Popescu
A. Aure, W. Decker, K. Hulek, S. Popescu, K. Ranestad
The Geometry of Bielliptic Surfaces in P^4
28 pages. AMSLaTeX 1.1
null
null
null
null
In 1988 Serrano \cite{Ser}, using Reider's method, discovered a minimal bielliptic surface in $\PP^4$. Actually he showed that there is a unique family of such surfaces and that they have degree 10 and sectional genus 6. In this paper we describe, among other things, the geometry of the embedding of the minimal biell...
[ { "version": "v1", "created": "Wed, 20 Jan 1993 11:44:54 GMT" } ]
2008-02-03T00:00:00
[ [ "Aure", "A.", "" ], [ "Decker", "W.", "" ], [ "Hulek", "K.", "" ], [ "Popescu", "S.", "" ], [ "Ranestad", "K.", "" ] ]
alg-geom
\section{Heisenberg invariants on $\Bbb P^2$} Here we collect some well-known facts about invariants of the Schr\"odinger representation of $H_3$, the Heisenberg group of level $3$. Let $x_0,x_1,x_2$ be a basis of $\mathrm H^\circ(\cal O_{\Bbb P^2}(1))$ and consider the dual of the Schr\"odinger representation of $H_3...
1993-04-09T17:12:04
9303
alg-geom/9303005
en
https://arxiv.org/abs/alg-geom/9303005
[ "alg-geom", "math.AG" ]
alg-geom/9303005
Roberto Paoletti
Roberto Paoletti
Free pencils on divisors
18 pages, amslatex
null
null
null
null
Let X be a smooth projective variety defined over an algebraically closed field, and let Y in X be a reduced and irreducible ample divisor in X. We give a numerical sufficient condition for a base point free pencil on $Y$ to be the restriction of a base point free pencil on $X$. This result is then extended to famili...
[ { "version": "v1", "created": "Sun, 28 Mar 1993 21:29:31 GMT" }, { "version": "v2", "created": "Fri, 9 Apr 1993 15:12:29 GMT" } ]
2008-02-03T00:00:00
[ [ "Paoletti", "Roberto", "" ] ]
alg-geom
\section{\bf {Introduction}} In algebraic geometry, it is rather typical that the embedding of a variety $Y$ in another variety $X$ forces strong constraints on the existence of free linear series on $Y$. For example, a classical result in plane curve theory states that the gonality of a smooth plane curve of deg...
1993-03-28T20:31:54
9303
alg-geom/9303004
en
https://arxiv.org/abs/alg-geom/9303004
[ "alg-geom", "math.AG" ]
alg-geom/9303004
Ron Donagi
Ron Donagi and Loring W. Tu
Theta Functions for $\SL(n)$ versus $\GL(n)$
10 pages, Latex
null
null
null
null
Over a smooth complex projective curve $C$ of genus $g$ let $\M (n,d)$ be the moduli space of semistable bundles of rank $n$ and degree $d$ on $C$, and $\SM (n,L)$, the moduli space of those bundles whose determinant is isomorphic to a fixed line bundle $L$ over $C$. Let $\theta_F$ and $\theta$ be theta bundles over ...
[ { "version": "v1", "created": "Sun, 28 Mar 1993 18:31:37 GMT" } ]
2008-02-03T00:00:00
[ [ "Donagi", "Ron", "" ], [ "Tu", "Loring W.", "" ] ]
alg-geom
\section{Theta bundles} \label{bundles} We recall here the definitions of the theta bundles on a fixed-determinant moduli space and on a full moduli space. Our definitions are slightly different from but equivalent to those in \cite{drezet-narasimhan}. For $L \in {\rm Pic} ^d (C)$, the Picard group of ${\cal SM} :=...