proposition: Lemma convC f g : conv f g =1 conv g f.
proof: Proof. move=> n; apply/eqP; rewrite /conv eqn_leq; apply/andP; split. apply/bigmin_leqP => i iLn. rewrite -{1}(subKn iLn) addnC. by apply: bigmin_inf (leq_subr _ _) (leqnn _). apply/bigmin_leqP => i iLn. rewrite -{1}(subKn iLn) addnC. by apply: bigmin_inf (leq_subr _ _) (leqnn _). Qed.
imports: mathcomp(all_ssreflect finmap)