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Back to Algebraic Geometry Seminar: Fall 2011

Algebraic Geometry Seminar


Date: Tuesday, Sep 20, 2011

Time: 3:30PM - 4:30PM

Location: LCB 222


William D. Gillam

Brown University

Title

Quotient schemes and stable pairs

Abstract

Let E be a rank two vector bundle over a Riemann surface C. The moduli space of stable pairs on E, in the sense of Pandharipande-Thomas, provides an alternative to the space of stable maps to E for the purpose of “counting” curves in the threefold E. The scaling action on E induces a torus action on the stable pairs moduli space. The moduli spaces of torus fixed stable pairs can be described as closed subschemes of products of quotient schemes of symmetric powers of E. The description is somewhat compatible with the obstruction theories. In favourable situations this can be used to express stable pairs invariants in terms of quotient scheme invariants—the latter being well-understood. In the “favourable situations” one thus obtains “explicit formulas” for the full descendant stable pairs theory of E.

Algebraic Geometry

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