/ John Wiltshire-Gordon: FI-modules in high degree

John Wiltshire-Gordon: FI-modules in high degree

November 5, 2019
4:30 pm - 5:30 pm

Abstract¬†Let FI be the category of finite sets and injections; an FI-module is a functor FI –> Ab. If M is a finitely generated FI-module, then a basic principle (actually, a theorem of Church–Ellenberg–Farb–Nagpal) guarantees that the behavior of M on large sets is determined by its behavior on small sets. We call the large-set behavior of an FI-module its “tail.” We give a finite description of the category of tails, and use it to compute some examples. This talk is based on joint work with Peter Patzt.