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Logic Seminar - Moshe Kamensky | Einstein Institute of Mathematics

Logic Seminar - Moshe Kamensky

Date: 
Wed, 19/04/202311:30-13:30
Location: 
Shprintzak 101

Title: Higher internal covers
Abstract: Internal covers describe a situation where two definable sets admit a definable bijection over some additional parameters. In this case, the automorphism group of one of them over the other becomes definable, yielding a definable version of Galois theory. Hrushovski realized that it is more canonical to attach a groupoid, rather than a group to such covers, and there is an equivalence between such covers and definable groupoids in the base theory. I will suggest a notion of ``higher'' internal covers, corresponding to higher definable groupoids.