Energy functions on moduli spaces of flat surfaces with erasing forest

Abstract

This paper follows on from Nguyen (Geom Funct Anal 20(1):192–228, 2010), in which we study flat surfaces with erasing forest, these surfaces are obtained by deforming the metric structure of translation surfaces, and their moduli space can be viewed as a deformation of the moduli space of translation surfaces. We showed that the moduli spaces of such surfaces are complex orbifolds, and admit a natural volume form μ Tr. The aim of this paper is to show that the volume of those moduli spaces with respect to μ Tr, normalized by some energy function involving the area and the total length of the erasing forest, is finite. Note that translation surfaces and flat surfaces of genus zero can be viewed as special cases of flat surfaces with erasing forest, and on their moduli space, the volume form μ Tr equals the usual ones up to a multiplicative constant. Using this result we obtain new proofs for some classical results due to Masur-Veech, and Thurston concerning the finiteness of the volume of the moduli space of translation sufaces, and of the moduli space of polyhedral flat surfaces.