Decreasing involutions and ${\mathbb{Z}}_2$-means

Natalia Jonard-Pérez, Ananda López-Poo

An $n$-mean on a topological space $X$ is a continuous symmetric map $p:X^n\to X$ satisfying $p(x,\dots ,x)=x$ for every $x\in X$. If $X$ is a $G$-space, such an $n$-mean is…