Super Asymptotically Nonexpansive Actions of Semitopological Semigroups on Frechet and Locally Convex Spaces

Abstract

Let LUC$(S)$ be the space of left uniformly continuous functions on a semitopological semigroup $S$. Suppose that $S$ is right reversible and $\operatorname{LUC}(S)$ has a left invariant mean. Let $(X,d)$ be a Fr\'echet space. Let $\tau$ be a locally convex topology of $X$ weaker than the $d$-topology such that the metric $d$ is $\tau$-lower semicontinuous. Let $K$ be a $d$--separable and $\tau$--compact convex subset of $X$. We show that every jointly $\tau$-continuous and super asymptotically $d$-nonexpansive action $S\times K\mapsto K$ of $S$ has a common fixed point. Similar results in the locally convex space setting are provided.