A Modular Curve of Level 9 and the Class Number One Problem

2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/220084In this note we give an explicit parametrization of the modular curve associated to the normalizer of a non-split Cartan subgroup of level 9. We determine all integral points of this modular curve. As an application, we give an alternative solution to the class number one problem.18 pagesNumber Theory11G05; 11G15; 11R29A Modular Curve of Level 9 and the Class Number One Problemtext