# University of Toronto's Symplectic Geometry Seminar

January 8, 2007, 3:10pm

BA 2165

## Tomoo Matsumura

### Boston University

## Lehn-Sorger algebra, Fantechi-Gottsche ring and a wreath
product orbifold

**Abstract: **
We will start with the definition of orbifold chomology of a global
quotient by a finite group, using Fantechi-Gottsche ring.
The ring multiplication is given by a very simple formula
due to Jarvis-Kaufmann-Kimura. We will explain the case of symmetric
product orbifolds and show how it generalizes to wreath product orbifolds.