On geometrical interpretation of thep-adic Maslov index

A set of selfdual lattices in a two-dimensionalp-adic symplectic space is provided by an integer valued metricd. A realization of the metric space (,d) as a graph is suggested and this graph has been linked to the Bruhat-Tits tree. An action of symplectic group on a set of cycles of length three of the graph is considered and a geometrical interpretation of thep-adic Maslov index is given in terms of this action.