BEGIN:VCALENDAR VERSION:2.0 PRODID:researchseminars.org CALSCALE:GREGORIAN X-WR-CALNAME:researchseminars.org BEGIN:VEVENT SUMMARY:Frances Kirwan (University of Oxford) DTSTART:20210126T140000Z DTEND:20210126T150000Z DTSTAMP:20260423T052923Z UID:ZAG/89 DESCRIPTION:Title: Mod uli of unstable objects in algebraic geometry\nby Frances Kirwan (Univ ersity of Oxford) as part of ZAG (Zoom Algebraic Geometry) seminar\n\n\nAb stract\nThe construction of the moduli spaces of stable curves of fixed ge nus is one of the classical applications of Mumford's geometric invariant theory (GIT)\, developed in the 1960s\; many other moduli spaces of 'stabl e' objects can be constructed using GIT\, as well as in other ways. The ai m of this talk is to explain how recent methods from a version of GIT for non-reductive group actions can help us to use suitable 'stability conditi ons' to stratify moduli stacks into locally closed strata such that not on ly the open 'stable' strata but also the 'unstable' strata have coarse mod uli spaces. In the case of moduli stacks of bundles over a nonsingular pro jective curve\, these stratifications refine the stratification by Harder- Narasimhan type. The talk is based on joint work with Gergely Berczi\, Vic ky Hoskins and Joshua Jackson.\n LOCATION:https://researchseminars.org/talk/ZAG/89/ END:VEVENT END:VCALENDAR