proposition: Lemma size_cast_bseq m n (eq_mn : m = n) (bs : m.-bseq T) : size (cast_bseq eq_mn bs) = size bs.
proof: Proof. by case: n / eq_mn. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype path)