BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Jeffrey Giansiracusa (Durham University) DTSTART:20231123T140500Z DTEND:20231123T150000Z DTSTAMP:20260423T003236Z UID:GaTO/89 DESCRIPTION:Title: To pology of the matroid Grassmannian\nby Jeffrey Giansiracusa (Durham Un iversity) as part of Geometry and topology online\n\nLecture held in Room B3.02 in the Zeeman Building\, University of Warwick.\n\nAbstract\nThe mat roid Grassmannian is the moduli space of oriented matroids\; this is an im portant combinatorial analogue of the ordinary oriented real Grassmannian. Thirty years ago MacPherson showed us that understanding the homotopy ty pe of this space can have significant implications in manifold topology\, such as providing combinatorial formulae for the Pontrjagin classes. In s ome easy cases\, the matroid Grassmannian is homotopy equivalent to the or iented real Grassmannian\, but in most cases we have no idea whether or no t they are equivalent. This question is known as MacPherson's conjecture. I'll show that one of the important homotopical structures of the orient ed Grassmannians has an analogue on the matroid Grassmannian: the direct s um monoidal product (which gives rise to topological K-theory) is E-infini ty.\n LOCATION:https://researchseminars.org/talk/GaTO/89/ END:VEVENT END:VCALENDAR