Generic surface homeomorphisms are almost continuum-wise expansive
Volume 271 / 2025
Fundamenta Mathematicae 271 (2025), 157-172
MSC: Primary 37B05; Secondary 37B45
DOI: 10.4064/fm240923-23-5
Published online: 24 October 2025
Abstract
We show that for a compact surface without boundary $M$ the set of cw-expansive homeomorphisms is dense in the set of all the homeomorphisms of $M$ with respect to the $C^0$ topology. After this we show that for a generic homeomorphism $f$ of $M$, for all $\varepsilon \gt 0$ there is a cw-expansive homeomorphism $g$ of $M$ which is $\varepsilon $-close to $f$ and is semiconjugate to $f$; moreover, if $\pi \colon M\to M$ is this semiconjugacy then $\pi^{-1}(x)$ is connected, does not separate $M$ and has diameter less than $\varepsilon $ for all $x\in M$.
