Non-Veech surfaces in $${\mathcal{H}^{\rm hyp}(4)}$$ H hyp ( 4 ) are generic

Abstract

We show that every surface in the component \({\mathcal{H}^{\rm hyp}(4)}\), that is the moduli space of pairs \({(M,\omega)}\) where M is a genus three hyperelliptic Riemann surface and \({\omega}\) is an Abelian differential having a single zero on M, is either a Veech surface or a generic surface, i.e. its \({{\rm GL}^{+}(2,\mathbb{R})}\)-orbit is either a closed or a dense subset of \({\mathcal{H}^{\rm hyp}(4)}\). The proof develops new techniques applicable in general to the problem of classifying orbit closures, especially in low genus. Combined with work of Matheus and the second author, a corollary is that there are at most finitely many non-arithmetic Teichmuller curves (closed orbits of surfaces not covering the torus) in \({\mathcal{H}^{\rm hyp}(4)}\).