Formula Normalizations in Verification

Abstract We apply and evaluate polynomial-time algorithms to compute two different normal forms of propositional formulas arising in verification. One the form is presented for first time. The solve word problem subtheories Boolean algebra: orthocomplemented bisemilattice (OCBSL) ortholattice (OL). Equality decides a sufficient (but not necessary) check equivalence formulas. Our contribution quadratic-time OL algorithm, which induces coarser than OCBSL thus more precise approximation equivalence. algorithm efficient even when input formula represented as directed acyclic graph. second evaluation part verification condition cache Stainless verifier Scala. results show that both normalization substantially increase hit ratio improve ability prove conditions by simplification alone. To gain further insights, we also compare on hardware circuit benchmarks, showing reduces size works well presence sharing.