proposition: Lemma star_plus_star: forall a b: regex, (a+b)# == (a#+b#)#.
proof: Proof. intros. rewrite star_plus_star_1. rewrite plus_com. rewrite star_plus_star_1. rewrite plus_com. reflexivity. Qed.
imports: ATBR(Common) ATBR(Classes) ATBR(Graph) ATBR(SemiLattice) ATBR(Monoid) ATBR(SemiRing) ATBR(KleeneAlgebra) ATBR(Model_RegExp) Coq(Bool)