Sets preserved by a large subgroup of the special linear group

Le Quang Hung, Thang Pham, Kaloyan Slavov

Let $E$ be a subset of the affine plane over a finite field ${\mathbb{F}}_q$. We bound the size of the subgroup of $S{L}_2({\mathbb{F}}_q)$ that preserves $E$. As a consequence, we show…