Colloquia/Fall18
Mathematics Colloquium
All colloquia are on Fridays at 4:00 pm in Van Vleck B239, unless otherwise indicated.
Fall 2015
Go to next semester, Spring 2016.
date | speaker | title | host(s) |
---|---|---|---|
September 4 | Isaac Goldbring (UIC) | On Kirchberg's embedding problem | Andrews/Lempp |
September 11 | Doron Puder (IAS) | Word-Measures on Groups | Gurevich |
September 18 | Izzet Coskun (UIC) | The geometry of points in the plane | Erman |
September 25 | Abbas Ourmazd (UW-Milwaukee) | Structure and Dynamics from Random Observations | Mitchell |
October 2 | |||
October 9 | Igor Mezic (UC Santa Barbara) | Budisic, Thiffeault | |
October 16 | Hadi Salmasian (Ottawa) | Gurevich | |
October 23 | Wisconsin Science Festival. | ||
October 30 | Ruth Charney (Brandeis) | Dymarz | |
November 6 | Reserved *S | ||
November 13 | Reserved *T | ||
November 20 | Reserved | ||
November 27 | University Holiday | No Colloquium | |
December 4 | Reserved | ||
December 11 | Reserved |
Abstracts
September 4: Isaac Goldbring (UIC)
Title: On Kirchberg's embedding problem
Abstract: In his seminal work on the classification program for nuclear C*-algebras, Kirchberg showed that a particular C*-algebra, the Cuntz algebra O2, plays a seminal role. Subsequent work with Chris Phillips showed that O2 also plays a prominent role in regards to the wider class of exact C*-algebras, and this led Kirchberg to conjecture that every C*-algebra is finitely representable in O2, that is, is embeddable in an ultrapower of O2. The main goal of this talk is to sketch a proof of a local finitary reformulation of this conjecture of Kirchberg. The proof uses model theory and in particular the notion of model-theoretic forcing. No knowledge of C*-algebras or model theory will be assumed. This is joint work with Thomas Sinclair.
September 11: Doron Puder (IAS)
Title: Word-Measures on Groups.
Abstract: Let w be a word in the free group on k generators, and let G be a finite (compact) group. The word w induces a measure on G by substituting the letters of w with k independent uniformly (Haar) chosen random elements of G and evaluating the product. Questions about word-measures on groups attracted attention in recent years both for their own sake and as a tool to analyze random walks on groups.
We will explain some properties of word-measure, give examples and state conjectures. We will also talk about recent results regarding word-measures on symmetric groups and word-measures on unitary groups.
September 18: Izzet Coskun (UIC)
Title: The geometry of points in the plane
Abstract: Grothendieck's Hilbert scheme of points is a smooth compactification of the configuration space of points in the plane. It has close connections with combinatorics, representation theory, mathematical physics and algebraic geometry. In this talk, I will survey some of the basic properties of this beautiful space. If time permits, I will discuss joint work with Arcara, Bertram and Huizenga on codimension one subvarieties of the Hilbert scheme.