Orbifold theory and modular extensions

Time:    10:30-12:00, 2022/11/16  

Venue:  BIMSA 1131

Zoom:   537 192 5549 （PW: BIMSA）

Abtract：

Orbifold theory studies a vertex operator algebra V under the action of a finite automorphism group G.  The main objective is to understand the module category of fixed point vertex operator subalgebra V^G. This talk will explain how to use the results on modular extensions  by Drinfeld-Gelaki-Nikshych-Ostrik and Lan-Kong-Wen to study the module category of V^G.  If  V is holomorphic then the V^G-module category is braided equivalent to the module category of some twisted Drinfeld double associated to a 3-cocycle in H^3(G,U(1)). This result has been conjectured by Dijkgraaf-Pasquier-Roche.  This is a joint work with Richard Ng and Li Ren