Calendar

Mar
23
Sat
Valentina Harizanov
Mar 23 @ 4:00 pm – 4:20 pm
Mar
24
Sun
Damir Dzhafarov
Mar 24 @ 9:00 am – 9:20 am
Richard Shore
Mar 24 @ 9:30 am – 9:50 am
Liang Yu
Mar 24 @ 10:00 am – 10:20 am
Mariya Soskova
Mar 24 @ 10:30 am – 10:50 am
Mar
27
Wed
Colloquium: Robin Deeley (U Colorado)
Mar 27 @ 3:30 pm – 4:30 pm

Speaker: Robin Deeley (U Colorado)

Title: Minimal dynamical systems

Abstract: A self-homeomorphism of a compact Hausdorff space is called minimal if each of its orbits is dense. I will discuss the following question: given a compact Hausdorff space does there exist a minimal homeomorphism on it? Although the answer is no, a similar question has a positive answer for any finite CW-complex. I will also discuss a number of explicit examples of minimal dynamical systems. All of our constructions are motivated by questions in C*-algebra theory. Nevertheless no knowledge of C*-algebras is required for the talk. This is joint work with Ian Putnam and Karen Strung.

Mar
29
Fri
Colloquium: Jeffrey Lyons @ Keller 401
Mar 29 @ 3:30 pm – 4:30 pm
Apr
12
Fri
Colloquium: Rohit Nagpal (U. Michigan) @ Keller 401
Apr 12 @ 3:30 pm – 4:30 pm

Speaker: Rohit Nagpal (U. Wisconsin)
Title: S_{infty}-equivariant modules over polynomial rings in infinitely many variables

Abstract: Let R be the polynomial ring k[x_1, x_2, ldots] in countably many variables. Cohen proved that S_{infty}-stable ideals in R satisfy the ascending chain condition. This makes the category of smooth equivariant R-modules a noetherian category. Smooth modules over R appear naturally in algebraic statistics and chemistry, and so it makes sense to study this category in detail. The first step in this direction is to understand its spectrum. In this talk, we describe this spectrum. In particular, we show that the S_{infty}-stable ideal I_n generated by n-variable discriminants is in this spectrum. We show that every nonzero S_{infty}-stable ideal must contain I_n for some large n, and so these ideals are of primary interest. We also mention some new algebraic properties of discriminants. This is a part of an ongoing project with Andrew Snowden.