Triangular modular curves of small genus (Q2679111)

Triangular modular curves are a generalization of modular curves that arise from quotients of the upper half-plane by congruence subgroups of hyperbolic triangle groups. In the present paper, the authors show that for any non-negative integer \(g\), there are only finitely many Borel-type triangular modular curves of genus \(g\) with admissible prime level. In particular, they determine the number of curves of genus at most two.