Triangles in the suborbital graphs of the normalizer of $\Gamma_0(N)$

Abstract

In this paper, we investigate a suborbital graph for the normalizer of $\Gamma_0(N) in PSL(2;R)$, where N will be of the form 2^4p^2 such that p > 3 is a prime number. Then we give edge and circuit conditions on graphs arising from the non-transitive action of the normalizer.

Keywords

• congruence subgroups, imprimitive group action, suborbital graphs