## EVENT DETAILS AND ABSTRACT

**Topology Seminar**
**Title:** Equivariantly Twisted Cohomology Theories

**Speaker:** John Lind

**Speaker Info:** Johns Hopkins University

**Brief Description:**

**Special Note**: **Note the unusual time!**

**Abstract:**

Twisted K-theory is a cohomology theory whose cocycles are like vector
bundles but with locally twisted transition functions. If we instead
consider twisted vector bundles with a symmetry encoded by the action
of a compact Lie group, the resulting theory is equivariant twisted K-theory. This subject has garnered much attention for its connections to conformal field theory and representations of loop groups. While twisted K-theory can be defined entirely in terms of
the geometry of vector bundles, there is a homotopy-theoretic formulation using the language of parametrized spectra. In fact, from
this point of view we can define twists of any multiplicative
generalized cohomology theory, not just K-theory. The aim of this
talk is to explain how this works, and then to propose a definition of
equivariant twisted cohomology theories using a similar framework.
The main ingredient is a structured approach to multiplicative
homotopy theory that allows for the notion of a G-torsor where G is a
grouplike A-infinity space.

**Date:** Tuesday, November 19, 2013

**Time:** 2:00pm

**Where:** Lunt 104

**Contact Person:** Prof. Paul Goerss

**Contact email:** pgoerss@math.northwestern.edu

**Contact Phone:** 847-491-8544

Copyright © 1997-2024
Department of Mathematics, Northwestern University.