fact: Definition dot' a b := if RegExp.is_one a then b else if RegExp.is_one b then a else RegExp.dot a b.
imports: ATBR(Common) ATBR(Classes) ATBR(Graph) ATBR(SemiLattice) ATBR(Monoid) ATBR(SemiRing) ATBR(KleeneAlgebra) ATBR(Model_RegExp) Coq(Bool)