Date:
Mon, 24/04/201712:00-14:00
Location:
Ross 63
We give an overview of some recent developments around the topic of the small index property for automorphism groups of countable structures. Specifically, we overview the following results of the authors:
(1) Countable free homogeneous structures in a locally finite irreflexive relational language have the strong small index property, thus generalizing Cameron's analogous result for the random graph.
(2) For $\aleph_0$-categorical structures the combination of strong small index property and no algebraicity implies reconstruction up to bi-definability, in analogy with Rubin's well-known $\forall \exists$-interpretation technique.
(3) The automorphism group of Hall's universal locally finite group has the strong small index property and it is complete.
