**SMS scnews item created by James East at Thu 1 Oct 2009 1107**

Type: Seminar

Distribution: World

Expiry: 2 Oct 2009

**Calendar1: 2 Oct 2009 1205-1255**

**CalLoc1: Carslaw 375**

Auth: jamese@bari.maths.usyd.edu.au

### Algebra Seminar

# Topological field theory in two dimensions and a filtration of Deligne-Mumford moduli spaces

### Ezra Getzler

#### Friday October 2, 12:05--12:55pm, Carslaw 375

###### Abstract

Deligne-Mumford moduli spaces are moduli spaces for projective curves with mild (normal crossing) singularities. They are important tools in mathematics and mathematical physics (their volumes are related to the KdV hierarchy, and they were used by de Jong in his famous theorem on the existence of smooth alterations). In this talk, I explain a way in which they resemble polyhedra: they carry a filtration such that the inclusion of the k'th filtrand is a k-homotopy equivalence.

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After the seminar we will take the speaker to lunch.

See the Algebra Seminar web page for information about other seminars in the series.

James East jamese@maths.usyd.edu.au