Restriction map in a regular reduction of $mathbf{SU}(n)^{2g}$

The quasi-Hamiltonian reduction of at a regular value, in the centre of SU(n), of the moment map is isomorphic to a moduli-space of semi-stable vector bundles over a Riemann surface. We describe the restriction map from the equivariant cohomology of to the cohomology of the moduli space in terms of natural multiplicative generators of these cohomologies. Received: May 28, 2002