In this talk, I will introduce a virtual variant of the quantized
Coulomb branch constructed by Braverman-Finkelberg-Nakajima, where the
convolution product is modified by a virtual intersection. The resulting
virtual Coulomb branch acts on the moduli space of quasimaps into the
holomorphic symplectic quotient T^*N///G. When G is abelian, over the torus
fixed points, this representation is a Verma module. The vertex function, a
K-theoretic enumerative invariant introduced by A. Okounkov, can be
expressed as a Whittaker function of the algebra. The construction also
provides a description of the quantum q-difference module. As an
application, this gives a proof of the invariance of the quantum
q-difference module under variation of GIT.

This will be a zoom seminar.
zoom URL: https://kyoto-u-edu.zoom.us/j/82353198201
passcode: The order of Weyl group of type $E_7$