proposition: Lemma p'nat_coprime pi m n : pi^'.-nat m -> pi.-nat n -> coprime m n.
proof: Proof. by move=> pi'm pi_n; rewrite (pnat_coprime pi'm) ?pnatNK. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(fintype div bigop)