Algebra and Algebraic Geometry Special Seminar - Allen Knutson -Schubert puzzles and quiver varieties
Title: Schubert puzzles and quiver varieties
Abstract: There are many formulae for the multiplication of Schubert classes in the cohomology ring of a Grassmannian, most famously the Littlewood-Richardson rule. Paul Zinn-Justin observed that my "puzzle" rule (with Terry Tao) for the generalization to equivariant cohomology is based on a solution to the Yang-Baxter equation. I'll explain Maulik-Okounkov's work showing how such solutions arise on "Nakajima quiver varieties", which led to the solution of many more problems in Schubert calculus. This work is joint with Paul Zinn-Justin and Iva Halacheva.
Location: Hamilton Hall 104