Topology Seminar

Title: Equivariantly Twisted Cohomology Theories
Speaker: John Lind
Speaker Info: Johns Hopkins University
Brief Description:
Special Note: Note the unusual time!

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
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