Stanford University Topology Seminar 2002-3

Unless otherwise noted, all seminars are on Tuesdays 4:00 - 5:00 pm in Room 383-N (3rd floor lounge of Math Building, Bldg 380).
There is tea at 3:30 on Tuesdays just outside of the the seminar room

Fall 2002 Schedule

October 1, 2002

Speaker: Constantin Teleman, Cambridge University
: Twisted K theory and the moduli of G-bundles over a Riemann surface

Abstract: We explain in this talk how the K-theoretic "intersection pairings" on the moduli of G-bundles over compact Riemann surface are controlled by defortmations of the Verlindealgebra, generalizing well-known results about powers of the determinant bundle. The moral justification of this fact is based on the theorem of Freed, Hopkins and the speaker, that the Verlinde algebra of G is expressible as a twisted K-theory of G, equivariant for its own conjugation action. The twistings in that theorem are multiples of the determinanttwisting of BU; the use of higher twistings allows one to incorporate other vector bundles on the moduli space.

October 8


October 15, 2002



October 22, 2002

Speaker: Gunnar Carlsson,  Stanford University

Title: Algebraic Topology and Feature Detection

Abstract: We are interested in locating various kinds of "features" of a geometric object, such as corners. edges, cone points, etc., when we are given the geometric object via a sampled "point cloud" from it.  I will describe various homological criteria which can be used as heuristics in finding these features.