Let B be the quaternion algebra over Q ramified at prime p and ∞ and O⊂B be a maximal order. How do you compute all integral right ideals I⊆O of a given norm?
You know BrandtModule(p).hecke_matrix(l) returns l-Brandt matrix of B and we can draw the l-Brandt graph from it, then O is a vertex and there are l+1 integral right O-ideals of norm l representing each of edge from O in general. I'd like to compute these ℓ-neighbors of O.