Non-commutative twisted Euler characteristic

Abstract

It is well known that given a finitely generated torsion module $M$ over the Iwasawa algebra $\mathbb Z_p[[\Gamma]]$, where $\Gamma \cong \mathbb Z_p$, there exists a continuous $p$-adic character $\rho$ of $\Gamma$ such that, for the twist $M(\rho)$ of $M$, the $\Gamma_n := \Gamma^{p^n}$ Euler characteristic, i.e. $\chi(\Gamma_n, M(\rho))$, is finite for every $n$. We prove a generalization of this result by considering modules over the Iwasawa algebra of a general $p$-adic Lie group $G$, instead of $\Gamma$. We relate this twisted Euler characteristic to the evaluation of the {\it Akashi series} at the twist and in turn use it to indicate some application to the Iwasawa theory of elliptic curves. This article is a natural generalization of the result established in [JOZ].