No Krasnoselskii number for general sets in ${\mathbb{R}}^2$

Chaya Keller, Micha A. Perles

For a family $\mathcal{F}$ of sets in ${\mathbb{R}}^d$, the Krasnoselskii number of $\mathcal{F}$ is the smallest $m$ such that for any $S\in \mathcal{F}$, if every $m$ points of $S…