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    Energy functions on moduli spaces of flat surfaces with erasing forest

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    Flat surfaces with erasing forest are obtained by deforming the flat metric structure of translation surfaces, the moduli space of such surfaces is a deformation of the moduli space of translation surfaces. On the moduli space of flat surfaces with erasing forest, one can define some energy function involving the area of the surface, and the total length of the erasing forest. Note that on this space, we have a volume form which is defined by using geodesic triangulations. The aim of this paper is to prove that the integral of the energy functions mentionned above with respect to this volume form is finite. As applications, we will use this result to recover some classical results due to Masur-Veech, and Thurston

    Regularity bounds for complexes and their homology

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    Let RR be a standard graded algebra over a field kk. We prove an Auslander-Buchsbaum formula for the absolute Castelnuovo-Mumford regularity, extending important cases of previous works of Chardin and R\"omer. For a bounded complex of finitely generated graded RR-modules LL, we prove the equality reg L=maxiZ{reg Hi(L)i}\text{reg}~ L=\max_{i\in \mathbb Z} \{\text{reg}~ H_i(L)-i\} given the condition depth Hi(L)dimHi+1(L)1\text{depth}~ H_i(L)\ge \dim H_{i+1}(L)-1 for all i<supLi<\sup L. As applications, we recover previous bounds on regularity of Tor due to Caviglia, Eisenbud-Huneke-Ulrich, among others. We also obtain strengthened results on regularity bounds for Ext and for the quotient by a linear form of a module.Comment: Final versio