proposition: Lemma p_eltNK pi x : pi^'^'.-elt x = pi.-elt x.
proof: Proof. exact: pnatNK. Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat seq div) mathcomp(fintype bigop finset prime fingroup morphism) mathcomp(gfunctor automorphism quotient action gproduct) mathcomp(cyclic)