Year: 2026
Type: preprint
Abstract: Let $X$ be a modular curve lying between $X_{0}(p)$ and $X_{1}(p)$, where $p \ge 13$ is prime. The cuspidal group of $X$ is the subgroup of its Jacobian generated by the equivalence classes of differences of cusps. In this paper, we give explicit formulae for the order of the cuspidal group, and two subgroups of it defined over the rationals.
Source: arXiv (Cornell University)
Author: Lupoian, Elvira
Language: English
Subfield: Geometry and Topology
Field: Mathematics
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7222944068