Transparent SL_n-skeins

Thu Mar 6, 2025 4:30 p.m.—5:30 p.m.
Exterior of Sheffield-Sterling-Strathcona Hall featuring a stone carving of Yale's coat of arms and motto

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Seminar: 
Quantum Topology and Field Theory

Event time: 
Thursday, March 6, 2025 - 4:30pm

Location: 
KT 801

Speaker: 
Francis Bonahon

Speaker affiliation: 
USC and MSU

Event description: 
For a Lie group G, the G-skein module of a 3-dimensional manifold M is a fundamental object in Witten’s interpretation of quantum knot invariants in the framework of a topological quantum field theory. It depends on a parameter q and, when this parameter q is a root of unity, the G-skein module contains elements with a surprising “transparency” property, in the sense that they can be traversed by any other skein without changing the resulting total skein. I will describe some (and conjecturally all) of these transparent elements in the case of the special linear group SL_n. The construction is based on the very classical theory of symmetric polynomials in n variables.