Graphs with $C_3_-free vertices are not universal fixers

Magdalena Lemańska, Monika Rosicka, Rita Zuazua

A non-isolated vertex $x\in V(G)$ is called $C_3$-free if $x$ belongs to no triangle of $G$. In \cite{BMW} Burger, Mynhardt and Weakley introduced the idea of universal fixers. L…