Week 2, Tuesday 21st January
Ningyuan Yao Definable Amenability of NIP Theories
In the last seminar, we had showed that in NIP theories, a global type which is finitely satisfiable in a small submodel is "Borel definable" over such submodel.
This time we will prove some properties of fsg groups, and finally, we will show that the only example of definable amenability group in NIP theories is fsg group. That means, with NIP, a group is definable amenability iff it is fsg group.