To any vertex algebra one can attach in a canonical way a certain Poisson variety, called the associated variety. Nilpotent Slodowy slices appear as associated varieties of admissible (simple) W-algebras. They also appear as Higgs branches of the Argyres-Douglas theories in 4d N=2 SCFT’s. These two facts are linked by the so-called Higgs branch conjecture. In this talk I will explain how to exploit the geometry of nilpotent Slodowy slices to study some properties of W-algebras whose motivation stems from physics. In particular I will be interested in collapsing levels for W-algebras. This is a joint work (still in preparation) with Tomoyuki Arakawa and Jethro van Ekeren.
During the last 20 years there has been a considerable literature on a collection of related mathematical topics: higher degree versions of Poncelet’s Theorem, certain measures associated to some finite Blaschke products and the numerical range of finite dimensional completely non-unitary contractions with defect index 1. I will explain that without realizing it, the authors of these works were discussing Orthogonal Polynomials on the Unit Circle (OPUC). This will allow us to use OPUC methods to provide illuminating proofs of some of their results and in turn to allow the insights from this literature to tell us something about OPUC. This is joint work with Andrei Martínez-Finkelshtein and Brian Simanek.
Poncelet’s Theorem, Paraorthogonal Polynomials and the Numerical Range of Truncated GGT matrices
C*-algebras have an incredible amount of both algebraic and analytic structure. We give a flavor for how the two worlds collide via examples and building up some of the basic structure, with an eye toward classifying commutative C*-algebras and stating everyone's favorite equivalence of categories. I'll also talk about some of my favorite C*-algebra facts.