BEGIN:VCALENDAR VERSION:2.0 PRODID:-//132.216.98.100//NONSGML kigkonsult.se iCalcreator 2.20.4// BEGIN:VEVENT UID:20251022T161704EDT-7552bzNFld@132.216.98.100 DTSTAMP:20251022T201704Z DESCRIPTION:Title: Matroids\, log-concavity\, and expanders\n\nAbstract: Ma troids are combinatorial objects that model various types of independence. They appear several fields mathematics\, including graph theory\, combina torial optimization\, and algebraic geometry. In this talk\, I will introd uce the theory of matroids along with the closely related class of polynom ials called strongly log-concave polynomials. Strong log-concavity is a fu nctional property of a real multivariate polynomial that translates to use ful conditions on its coefficients. Discrete probability distributions def ined by these coefficients inherit several of these nice properties. I wil l discuss the beautiful real and combinatorial geometry underlying these p olynomials and describe applications to random walks on the faces of simpl icial complexes. Consequences include proofs of Mason's conjecture that th e sequence of numbers of independent sets of a matroid is ultra log-concav e and the Mihail-Vazirani conjecture that the basis exchange graph of a ma troid has expansion at least one. This is based on joint work with Nima An ari\, Kuikui Liu\, and Shayan Oveis Gharan.\n\n \n DTSTART:20200114T203000Z DTEND:20200114T213000Z LOCATION:Room 708\, Burnside Hall\, CA\, QC\, Montreal\, H3A 0B9\, 805 rue Sherbrooke Ouest SUMMARY:Cynthia Vinzant (North Carolina State University) URL:/mathstat/channels/event/cynthia-vinzant-north-car olina-state-university-304111 END:VEVENT END:VCALENDAR