Invariant distributions on projective spaces over local fields

Abstract

Let $\Gamma$ be an $\widetilde A_n$ subgroup of $PGL_{n+1}(K)$, with $n\ge 2$, where $K$ is a local field with residue field of order $q$ and let $\bb P^n_{K}$ be projective $n$-space over $K$. The module of coinvariants $H_0(\Gamma; C(P^n_{K},Z))$ is shown to be finite. Consequently there is no nonzero $\Gamma$-invariant $Z$-valued distribution on $P^n_{K}$.