Chen-Ruan cohomology and moduli spaces of parabolic bundles over a Riemann surface

Abstract

Let $(X,D)$ be an $m$-pointed compact Riemann surface of genus at least $2$. For each $x\in D$, fix full flag and concentrated weight system $\alpha$. Let $P{\mathcal{M}}_{\xi }$ denote the moduli space of semi-stable parabolic vector bundles of rank $r$ and determinant $\xi$ over $X$ with weight system $\alpha$, where $r$ is a prime number and $\xi$ is a holomorphic line bundle over $X$ of degree $d$ which is not a multiple of $r$. We compute the Chen-Ruan cohomology of the orbifold for the action on $P{\mathcal{M}}_{\xi }$ of the group of $r$-torsion points in ${\mathrm{Pic}}^0(X)$.

12 pages