Algebra Seminar talk
2025-11-14
Javier de la Nuez Gonzalez
Sharply k-homogeneous actions on relational structures
Abstract:
We say that an action by isomorphisms of a group G on a relational structure M is sharply k-homogeneous if for any two tuples of distinct elements of M, a and a', which are in the same orbit under the diagonal action of Aut(M) there is exactly one element g in G mapping a to a'. I will discuss recent work joint with Rob Sullivan in which we establish sufficient conditions for the existence of sharply k-homogeneous actions of finitely generated virtually free groups on relational Fräissé limits.