fact: Fixpoint ror_cnf (f f':list clause) := match f with | nil => (cnf_tt, null) | e :: rst => let (rst_f',t) := ror_cnf rst f' in let (e_f', t') := ror_clause_cnf e f' in (rst_f' +++ e_f', merge t t') end.
imports: List Refl Bool Relation_Definitions Setoid