1 INTRODUCTION

2 METHODOLOGY

2.1 Sample selection

2.2 Hertzsprung–Russell diagram

2.3 Proper motions

2.4 Photometry

3 KNOWN ULTRACOOL DWARFS IN THE ALHAMBRA AND COSMOS FIELDS

4 SPECTROSCOPIC FOLLOW-UP

5 SIMULATIONS OF ULTRACOOL DWARF DETECTIONS IN THE EUCLID WIDE SURVEY

6 CONCLUSIONS