11 avril 2016 à 15 juillet 2016
Institut Henri Poincaré
Fuseau horaire Europe/Paris

Behrend

Kai Behrend, University of British Columbia

Title:   The spectrum of the inertia operator on the motivic Hall algebra

Abstract:  Following an idea of Bridgeland, we study the operator on the K-group of algebraic stacks, which takes a stack to its inertia stack.  We prove that the inertia operator is diagonalizable when restricted to nice enough stacks, including those with algebra stabilizers.  We use these results to prove a structure theorem for the motivic Hall algebra of a projective variety, and give a more conceptual definition of virtually indecomposable stack function.  This is joint work with Pooya Ronagh.