proposition: Lemma leq_card_tuple : forall (t : n.-tuple T), #|t| <= n.
proof: Proof. by move=> t; move: (card_size t); rewrite size_tuple. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(choice fintype tuple finset)