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Back to Algebraic Geometry Seminar: Spring 2019

Algebraic Geometry Seminar


Date: Tuesday, Apr 2, 2019

Time: 3:30PM - 4:30PM

Location: LCB 222


Hsian-Hua Tseng

Ohio State University

Title

Relative and orbifold Gromov-Witten invariants

Abstract

For a smooth projective variety X containing a smooth irreducible divisor D, the question of counting curves in X with prescribed contact conditions along D is a classical one in enumerative geometry. In more modern approaches to this question, there are two ways to define these counts: as Gromov-Witten invariants of X relative to D, or as Gromov-Witten invariants of the stack X_{D,r} of r-th roots of X along D (for r large). In genus 0, explicit calculations in examples suggested that these two sets of Gromov-Witten invariants are always the same, whether they actually count curves or not. This is proven in full generality by Abramovich-Cadman-Wise. The situation in genus > 0 is not so simple, as an example of D. Maulik showed that the two sets of Gromov-Witten invariants are not equal, even in genus 1. In this talk, we’ll explain how these two sets of Gromov-Witten invariants are related in all genera, in full generality. This is based on a joint work with Fenglong You.

Algebraic Geometry

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