Reduction of stabilizers and generalized Donaldson-Thomas invariants

Abstract: Starting with a sufficiently nice Artin stack, we explain a canonical blowup procedure that produces a Deligne-Mumford stack, resolving the locus of points with infinite automorphism group. This construction can be applied to moduli stacks parametrizing semistable sheaves or complexes on Calabi-Yau threefolds. We show that their stabilizer reductions admit natural virtual fundamental cycles, allowing us to define generalized Donaldson-Thomas invariants which act as counts of these objects. Everything in this talk is (maybe not so) secretly expected to be the shadow of a corresponding phenomenon in derived algebraic geometry, giving a new, derived perspective on Donaldson-Thomas invariants.

Based on joint work with Young-Hoon Kiem and Jun Li and joint work in progress with Jeroen Hekking and David Rydh.

algebraic geometry

Audience: researchers in the topic

( slides | video )

Comments: The synchronous discussion for Michail Savvas’ talk is taking place not in zoom-chat, but at tinyurl.com/2022-04-08-ms (and will be deleted after ~3-7 days).

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Stanford algebraic geometry seminar

Series comments: The seminar was online for a significant period of time, but for now is solely in person. More seminar information (including slides and videos, when available): agstanford.com

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