BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Navid Nabijou DTSTART:20211123T150000Z DTEND:20211123T160000Z DTSTAMP:20260423T052830Z UID:Freemath/66 DESCRIPTION:Title: Enumerative invariants of 3-fold flops: hyperplane arrangements and wall -crossing\nby Navid Nabijou as part of Free Mathematics Seminar\n\n\nA bstract\n3-fold flopping contractions form a fundamental building block of the higher-dimensional Minimal Model Program. They exhibit extremely rich geometry\, which has been investigated by many people over the past half- century. I will present an elegant and visually-pleasing relationship betw een enumerative invariants of flopping contractions and certain hyperplane arrangements constructed combinatorially from root system data. I will di scuss both Gopakumar-Vafa (GV) and Gromov-Witten (GW) invariants\, explain ing how these are related to one another and how they are encoded in finit e and infinite arrangements\, respectively. Finally\, I will discuss wall- crossing: our combinatorial approach allows us to explicitly construct flo ps from root system data\, leading to a new “direct” proof of the Crep ant Transformation Conjecture\, with a very explicit formulation. This is joint work with Michael Wemyss.\n LOCATION:https://researchseminars.org/talk/Freemath/66/ END:VEVENT END:VCALENDAR