proposition: Lemma cprod_inf7 a b: natp a -> a <> \0c -> infinite_c b -> a *c b = b.
proof: Proof. move => /NatP an anz ib; rewrite cprodC. exact: (cprod_inf (cle_fin_inf an ib) ib anz). Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat)