Algebra/Topology seminar Mike Hopkins

Title:  Polynomial projectors

Abstract:  A projector is a finite matrix P which squares to itself. Given a projector P over a ring R one can ask how many new projectors one can make whose entries are polynomials in the entries of P. This talk will describe joint work with Aravind Asok and Tom Bachmann which gives a relatively complete answer to this question when R is a regular ring over an algebraically closed field.