Speaker: Alex Fink (NCSU)

Title: K-classes for matroids and equivariant localisation

Abstract: Torus orbit closures on the Grassmannian are naturally associated to realisable matroids. We generalise this construction to associate a class in equivariant K-theory to every matroid, nonrealisable ones included, and study these classes using the methods of equivariant localisation. This leads to a geometric interpretation of the Tutte polynomial, as well as of an invariant of Speyer's pertaining to combinatorial bounds on linear spaces in tropical geometry. This is joint work with David Speyer.