BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Kris Shaw (University of Oslo) DTSTART:20230307T200000Z DTEND:20230307T210000Z DTSTAMP:20260423T024616Z UID:Matroids/40 DESCRIPTION:Title: The birational geometry of matroids\nby Kris Shaw (University of Osl o) as part of Matroids - Combinatorics\, Algebra and Geometry Seminar\n\nL ecture held in Room 210 The Fields Institute.\n\nAbstract\nIn this talk\, I will consider isomorphisms of Bergman fans of matroids. Motivated by al gebraic geometry\, such isomorphisms can be considered as matroid analogs of birational maps. If the matroids in question are not totally disconnect ed\, I will explain that an isomorphism respecting their fine fan structur es must be induced by a matroid isomorphism. However\, if we switch to the coarse fan structure\, this is no longer the case. I will introduce Cremo na automorphisms of the coarse structure of certain Bergman fans. These pr oduce a class of Bergman fan isomorphisms which are not induced by matroid automorphisms. I will then explain that the automorphism group of the coa rse fan structure is generated by matroid automorphisms and Cremona maps i n the case of rank 3 matroids which are not parallel connections and for m odularly complemented matroids. This is based on joint work with Annette W erner.\n LOCATION:https://researchseminars.org/talk/Matroids/40/ END:VEVENT END:VCALENDAR