Galois coinvariants of the unramified Iwasawa modules of multiple ${\mathbb{Z}}_p$-extensions

Takashi Miura, Kazuaki Murakami, Rei Otsuki +1

For a CM-field $K$ and an odd prime number $p$, let ${\tilde{K}}^{\prime }$ be a certain multiple ${\mathbb{Z}}_p$-extension of $K$. In this paper, we study several basic properties of the u…