2 problems

Let $G$ be a group and let $\phi:G\to G$ be an automorphism. Write $R(\phi)$ for the number of $\phi$-conjugacy classes and $R_*(\phi)$ for the dimension, or cardinality in the fin…

Let $G$ be a group, let $\phi:G\to G$ be an automorphism, let $R(\phi)$ denote its Reidemeister number, let $C^*(G)$ be the group $C^*$-algebra, and let…