Bounds for canonical Green's functions at cusps

Abstract

Let $Γ$ be a cofinite Fuchsian subgroup. The canonical Green's function associated with $Γ$ arises in Arakelov theory when establishing asymptotics for Arakelov invariants of the modular curve associated with some congruence subgroup of level $N$ with a positive integer $N$. More precisely, in the known cases, canonical Green's functions at certain cusps contribute to the analytic part of the asymptotics for the self-intersection of the relative dualizing sheaf. In this article, we prove canonical Green's function of a cofinite Fuchsian subgroup at cusps bounded by the scattering constants, the Kronecker limit functions, and the Selberg zeta function of the group $Γ$. Then as an application, we prove an asymptotic expression of the canonical Green's function associated with $Γ_0(N)$, for any positive integer $N$.