Per here the first hints of moonshine appeared around 1974 when Andrew Ogg noticed that quotienting the hyperbolic plane by normalizers of the Hecke Congruence subgroups $\Gamma_{0}(p)$ has genus zero iff p is a divisor of the order of the monster group.
A natural question then to ask is can we try to extend the result to genus 1? That is:
- For which $p$ is the quotient of the hyperbolic plane by the normalizer $\Gamma_{0}(p)^+$ of the hecke congruence subgroup $\Gamma_{0}(p) \subset \text{SL}(2,\mathbb{R}) $, a riemann surface of genus 1?
- If its a finite list of p, does that set of $p$ divide anything interesting?
- If its an infinite list, does that sequence of $p$'s divide some other interesting sequence?
Has there been any prior work on (1)?