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TCS+ Talk

Wednesday, March 6, 2019
10:00am to 11:00am
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Annenberg 322
Strongly log concave polynomials, high dimensional simplicial complexes, and an FPRAS for counting Bases of Matroids
Shayan Oveis Gharan, University of Washington,


A matroid is an abstract combinatorial object which generalizes the notions of spanning trees, and linearly independent sets of vectors. I will talk about an efficient algorithm based on the Markov Chain Monte Carlo technique to approximately count the number of bases of any given matroid.

The proof is based on a new connections between high dimensional simplicial complexes, and a new class of multivariate polynomials called completely log-concave polynomials. In particular, we exploit a fundamental fact from our previous work that the bases generating polynomial of any given matroid is a log-concave function over the positive orthant.

Based on joint works with Nima Anari, Kuikui Liu, and Cynthia Vinzant.

For more information, please contact Bonnie Leung by email at