proposition: Lemma reflexive_extends: forall s, invariant s -> extends s s.
proof: Proof. intros s Hs. constructor; auto. reflexivity. Qed.
imports: ATBR(Common) ATBR(Classes) ATBR(Graph) ATBR(Monoid) ATBR(SemiLattice) ATBR(SemiRing) ATBR(KleeneAlgebra) ATBR(MxGraph) ATBR(MxSemiLattice) ATBR(MxSemiRing) ATBR(MxKleeneAlgebra) ATBR(DKA_Definitions) ATBR(DKA_StateSetSets) ATBR(Numbers) ATBR(Utils_WF)