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Quantum Lefschetz without curves

组织者

阿尔坦·谢什马尼 , 杨南君 , 袁北彗

演讲者

Richard Thomas

时间

2024年03月07日 15:00 至 16:00

地点

A6-101

线上

Zoom 638 227 8222 (BIMSA)

摘要

The original “Quantum Lefschetz principle” enumerated genus 0 curves in a quintic 3-fold by considering them as curves in ℙ^4 and then imposing the constraint that the quintic polynomial vanishes on them. I will review how this has to be modified in higher genus using the “p-fields” of Chang-Li and Guffin-Sharpe-Witten. Then I will describe joint work with Jeongseok Oh developing a general theory, independent of curve counting. The upshot is two formulae for the virtual cycle of a quasi-smooth derived scheme (or DM stack) cut out of another quasi-smooth derived scheme by a section of a 2-term complex of vector bundles.