Title: Gerbes and Twisted Orbifold Quantum Cohomology

Time: Thursday Dec. 20, 10:00-12:00.

Speaker: Professor Xiaoqin Yin (Sichuan University)

Venue: Room 09 at Quan-Zhai (全斋), Beijing International Center for Mathematical Research, Peking University.

Abstract:
Given a gerbe with connection on an orbifold, we can construct a holonomy line bundle over the loop space of the orbifold. Its restriction to the space of constant loops (inertia orbifold) is nontrivial but flat. It is actually an inner local system.

Furthermore, the pullback of a flat gerbe by an orbifold stable map induces a flat trivialization.

We will use the flat trivialization to twist orbifold Gromov-Witten invariants, and then compute these invariants in the case of a smooth manifold and a discrete torsion on a global quotient orbifold.