proposition: Lemma add_Zp_1 p (x : 'Z_p) : x + 1 = ordS x.
proof: Proof. by rewrite addrC add_1_Zp. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool choice eqtype ssrnat seq div) mathcomp(fintype bigop finset prime fingroup) mathcomp(ssralg finalg countalg)