A Unifying Principle for Clause Elimination in First-Order Logic

Preprocessing techniques for formulas in conjunctive normal form play an important role in first-order theorem proving. To speed up the proving process, these techniques simplify a formula without affecting its satisfiability or unsatisfiability. In this paper, we introduce the principle of implication modulo resolution, which allows us to lift several preprocessing techniques—in particular, several clause-elimination techniques—from the SAT-solving world to first-order logic. We analyze confluence properties of these new techniques and show how implication modulo resolution yields short soundness proofs for the existing firstorder techniques of predicate elimination and blocked-clause elimination.