31st NRW Topology Meeting


+++   Bochum (GERMANY)   +++   Friday, May 10 and Saturday, May 11, 2019   +++


Martina Rovelli (Johns Hopkins University)

What features are detected by characteristic classes?

We propose a uniform interpretation of characteristic classes as complete obstructions to the reduction of the structure group of a principal bundle, and to the existence of an equivariant extension of a certain homomorphism defined a priori only on a single fiber. We then define a family of invariants for principal bundles that detect the number of group reductions associated to certain characteristic classes that a principal bundle admits.

Organizers: Gerd Laures, Viktoriya Ozornova and Björn Schuster