Introduction
1. Probes and Forecasting Approach
1.1 Surveys
1.2 Fiducial Cosmology
1.3 Angular Power Spectra
2. Forecasts: Combining Galaxy Surveys & GW Detectors
2.1 Settings
2.2 The νΛCDM Scenario
2.3 The νΛCDM Scenario with Free $M_{\nu}$
2.4 The $\nu w_{0}w_{a}$ CDM Scenario
2.5 The $\nu w_{0}w_{a}$ CDM Scenario with Free $M_{\nu}$
Conclusions