Hi everyone
My question seems classic, so it might be trivial or simple, therefore I am sorry in this case. Let $A\subseteq \mathbb{F}_p$ be a set with size $a$, and let $G$ be the subgroup generated by $A$. I am interested in $|G|$ for instance how big is it?. I guess if $|A|\gg \sqrt{p}$ then $G=\mathbb{F}_p$

