Tuesday, April 24, 2018
East Bridge 201
Moore-Tachikawa 2d TQFTs whose values are holomorphic symplectic varieties
Hiraku Nakajima, Department of Mathematics, Kyoto University
Moore-Tachikawa asked what are the Higgs branches of 4d N=2 class S theories associated with Riemann surfaces with punctures as holomorphic symplectic varieties. They are supposed to satisfy analog of gluing rules of 2d TQFT, where the composition of homomorphisms is replaced by hamiltonian reduction. I will explain this conjecture and its solution for type A via our recent construction of Coulomb branches of 3d N=4 gauge theories. More detail of the construction and generalization to other types will be explained in a seminar on Wednesday.