proposition: Lemma swapK A B : (@swap A B) \o swap = @id (B * A).
proof: Proof. by rewrite boolp.funeqE => -[]. Qed.
imports: mathcomp(all_ssreflect ssralg fingroup perm matrix) mathcomp(all_algebra vector reals normedtype) mathcomp(mathcomp_extra boolp) mathcomp(Rstruct) ssrR logb realType_ext ssr_ext ssralg_ext bigop_ext