Motivated by recent interests in fracton topological phases, we explore the interplay between gapped 2D $\mathbb{Z}_N$ topological phases which admit fractional excitations with restricted mobility and geometry of the lattice on which such phases are placed. We investigate the properties of the phases in a new geometric context -- graph theory. By placing the phases on a 2D lattice consisting of two arbitrary connected graphs, $G_x\boxtimes G_y$, we study the behavior of fractional excitations of the phases. We derive the formula of the ground state degeneracy of the phases, which depends on invariant factors of the Laplacian.

25 pages, 6 figures