The Moduli Space of (1,11)-Polarized Abelian Surfaces is Unirational
We prove that the moduli space $\cal A$11lev of <$>(1,11)-polarized Abelian surfaces with level structure of canonical type is birational to Klein's cubic hypersurface in P4. Therefore, $\cal A$11lev is unirational but not rational, and there are no Γ11-cusp forms of weight 3. The same methods also provide an easy proof of the rationality of $\cal A$9lev.
Key Words: Abelian surfaces; moduli; Kleine's cubic hypersurface.