Some questions of Arhangel'skii on rotoids
Some questions of Arhangel'skii on rotoids
A <i>rotoid</i> is a space $X$ with a special point $e \in X$ and a homeomorphism $F: X^2 \rightarrow X^2$ having $F(x,x) = (x,e)$ and $F(e,x) = (e,x)$ for every $x \in X$. If <i>any</i> point of $X$ can be used as the point $e$, then $X$ is called a …