Marco Bruni                                  GGI Florence, October 2006
Some open questions
§Is the singularity locally or globally isotropic? (issue similar for de Sitter, cf. Starobinski)
§Is it extendable (geodesic completeness)?
§Causality?
§Bounces in closed FRW models: are these stable? Can they be used to model pre-big-bang and perturbations? (currently exploring this idea with Valerio Bozza in Salerno; cf. Brandenberger et al. vs. Kaloper et al. 2006).
§Does isotropy survive in strong non-linear regime? A first attempt at Bianchi IX seems to confirm it (in progress with Coley and Woei Chet).