An Elementary Proof of the Restricted Invertibility Theorem

COMPUTER SCIENCE AND DISCRETE MATHEMATICS SEMINAR II
Topic:An Elementary Proof of the Restricted Invertibility Theorem
Speaker:Nikhil Srivastava
Affiliation:Member, School of Mathematics
Date:Tuesday, November 9
Time/Room:10:30am - 12:30pm/S-101

We give an elementary proof of a generalization of Bourgain and Tzafriri's Restricted Invertibility Theorem, which says roughly that any matrix with columns of unit length and bounded operator norm has a large coordinate subspace on which it is well-invertible. Our proof gives the tightest known form of this result, is constructive, and provides a deterministic polynomial time algorithm for finding the desired subspace. Joint work with Dan Spielman.