I will report on recent joint work with Macpherson about pseudofinite groups in the omega-categorical setting, suggesting that such groups might be finite-by-abelian-by-finite.

Two groups are elementarily equivalent if they have the same sets of true firstorder group theoretic sentences. We prove that if the homeomorphism groups of two compact connected manifolds are elementarily equivalent, then the manifolds are homeomorphic. This generalizes Whittaker's theorem on isomorphic homeomorphism groups (1963) without relying on it. Joint work with Thomas Koberda (UVa) and Javier de la Nuez-Gonzalez (KIAS).