Quantum Topology / Hopf Algebra Seminar
Jim Otto
UIC
From monoid actions and Kripke worlds to categories, presheaves, and toposes
Abstract: We work towards an understanding of Cohen's forcing using toposes of double negation sheaves
roughly as in Johnstone's Dover book. We see how both monoid actions (and thus group actions) on sets
and Kripke structures over graphs of worlds generalize to presheaves over categories.
We begin to use the Yoneda lemma to see that categories of presheaves are toposes.
Thursday January 12, 2017 at 2:00 PM in SEO 612