On a generalization of the Cartwright–Littlewood fixed point theorem for planar homeomorphisms

We prove a generalization of the fixed point theorem of Cartwright and Littlewood. Namely, suppose that $h:\mathbb{R}^{2}\rightarrow \mathbb{R}^{2}$ is an orientation preserving planar homeomorphism, and let $C$ be a continuum such that $h^{-1}(C)\cup C$ is acyclic. If there is a $c\in C$ such that $\{h^{-i}(c):i\in \mathbb{N}\}\subseteq C$, or $\{h^{i}(c):i\in \mathbb{N}\}\subseteq C$, then $C$ also contains a fixed point of $h$. Our approach is based on Brown’s short proof of the result of Cartwright and Littlewood. In addition, making use of a linked periodic orbits theorem of Bonino, we also prove a counterpart of the aforementioned result for orientation reversing homeomorphisms, that guarantees a $2$-periodic orbit in $C$ if it contains a $k$-periodic orbit ($k>1$).