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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


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.

October 9: Igor Mezic (UC Santa Barbara)

Past Colloquia

Spring 2015

Fall 2014

Spring 2014

Fall 2013

Spring 2013

Fall 2012