Degree one cohomology with twisted coefficients of the mapping class group

Abstract

Let $Γ$ be the mapping class group of an oriented surface $Σ$ of genus g with r boundary components. We prove that the first cohomology group $H^1(Γ, O(M_{SL(2, C)})^*)$ is non-trivial, where the coefficient module is the dual of the space of algebraic functions on the $SL(2, C)$ moduli space over $Σ$.

19 pages, 11 figures