Register for: AustMS2017

Details of talk

TitleUltrafilters
PresenterRichard Garner (Macquarie University)
Author(s)Dr Richard Garner
SessionCategory Theory, Algebraic Topology, K-Theory
Time14:30:00 2017-12-15
Abstract


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Ultrafilters are important structures in areas of mathematics as diverse as
combinatorics, model theory, topology and dynamical systems. In this talk, I
explain how the notions of ultrafilter, ultrapower, product of ultrafilters, and
Rudin--Keisler ordering of ultrafilters, are all encapsulated in the following
result: the category of finite-coproduct-preserving endofunctors of the category
of sets is a presheaf category.