More on symplectic graphs modulo pn

Meemark and Prinyasart [10] proved by combinatorial method that the symplectic graph modulo pn is strongly regular when ν=1, and is arc transitive when p is an odd prime. In this paper, combining matrix method and elementary number theory, we continue this research, and prove that is arc transitive for any prime p. Furthermore, we determine the suborbits of the symplectic group modulo pn on , and show that is a strictly Deza graph when ν≥2 and n≥2.