proposition: Lemma non_strict_not_strict: forall a, non_strict a -> ~ strict a.
proof: Proof. induction 1; intro Ha; inversion_clear Ha; auto. Qed.
imports: ATBR(Common) ATBR(Classes) ATBR(Graph) ATBR(SemiLattice) ATBR(Monoid) ATBR(SemiRing) ATBR(KleeneAlgebra) ATBR(Model_RegExp) Coq(Bool)