On Helly numbers of exponential lattices

Gergely Ambrus, Martin Balko, Nóra Frankl +2

Given a set $S\subseteq {\mathbb{R}}^2$, define the \emph{Helly number of $S$}, denoted by $H(S)$, as the smallest positive integer $N$, if it exists, for which the following statem…