Date:
Wed, 09/03/202211:00-13:00
Location:
Via zoom: Meeting ID: 891 8649 9242 , Passcode: 360371
Title: "on large externally definable subsets in NIP"
Joint work with Martin Bays and Pierre Simon
Abstract:
Joint work with Martin Bays and Pierre Simon
Abstract:
Suppose that M is a model of an NIP theory, and X an externally definable subset: for some elementary extension N of M, and some c from N, X = {a\in M : phi(a,c) holds}.
How large should X be to contain an infinite M-definable subset? Chernikov and Simon asked whether aleph1 is enough. I will discuss this question and relate it to questions in model theory and infinite combinatorics.