The quotients of the $p$-adic group ring of a cyclic group of order $p$

Abstract

We classify, up to isomorphism, the $\mathbb{Z}_pG$-modules of rank $1$ (i.e., the quotients of $\mathbb{Z}_pG$) for $G$ cyclic of order $p$, where $\mathbb{Z}_p$ is the ring of $p$-adic integers. This allows us in particular to determine effectively the quotients of $\mathbb{Z}_pG$ which are cohomologically trivial over $G$. There are natural zeta functions associated to $\mathbb{Z}_pG$ for which we give an explicit formula.