Evaluating QBF Solvers: Quantifier Alternations Matter
Abstract
We present an experimental study of the effects of quantifier alternations on the evaluation of quantified Boolean formula (QBF) solvers. The number of quantifier alternations in a QBF in prenex conjunctive normal form (PCNF) is directly related to the theoretical hardness of the respective QBF satisfiability problem in the polynomial hierarchy. We show empirically that the performance of solvers based on different solving paradigms substantially varies depending on the numbers of alternations in PCNFs. In related theoretical work, quantifier alternations have become the focus of understanding the strengths and weaknesses of various QBF proof systems implemented in solvers. Our results motivate the development of methods to evaluate orthogonal solving paradigms by taking quantifier alternations into account. This is necessary to showcase the broad range of existing QBF solving paradigms for practical QBF applications. Moreover, we highlight the potential of combining different approaches and QBF proof systems in solvers.
References
- 1.Atserias, A., Oliva, S.: Bounded-width QBF is PSPACE-complete. In: STACS. LIPIcs, vol. 20, pp. 44–54. Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik (2013)Google Scholar
- 2.Ayari, A., Basin, D.: Qubos: deciding quantified boolean logic using propositional satisfiability solvers. In: Aagaard, M.D., O’Leary, J.W. (eds.) FMCAD 2002. LNCS, vol. 2517, pp. 187–201. Springer, Heidelberg (2002). https://doi.org/10.1007/3-540-36126-X_12CrossRefGoogle Scholar
- 3.Balint, A., Belov, A., Järvisalo, M., Sinz, C.: Overview and analysis of the SAT challenge 2012 solver competition. Artif. Intell. 223, 120–155 (2015)CrossRefGoogle Scholar
- 4.Balyo, T., Biere, A., Iser, M., Sinz, C.: SAT race 2015. Artif. Intell. 241, 45–65 (2016). https://doi.org/10.1016/j.artint.2016.08.007MathSciNetCrossRefzbMATHGoogle Scholar
- 5.Balyo, T., Heule, M.J.H., Järvisalo, M.: SAT competition 2016: recent developments. In: AAAI, pp. 5061–5063. AAAI Press (2017)Google Scholar
- 6.Beyersdorff, O., Blinkhorn, J., Hinde, L.: Size, cost and capacity: a semantic technique for hard random QBFs. In: ITCS. LIPIcs, vol. 94, pp. 9:1–9:18. Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik (2018)Google Scholar
- 7.Beyersdorff, O., Chew, L., Janota, M.: Proof complexity of resolution-based QBF calculi. In: STACS. LIPIcs, vol. 30, pp. 76–89. Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik (2015)Google Scholar
- 8.Beyersdorff, O., Chew, L., Janota, M.: Extension variables in QBF Resolution. In: Beyond NP Workshop, AAAI Workshops, vol. WS-16-05. AAAI Press (2016)Google Scholar
- 9.Beyersdorff, O., Hinde, L., Pich, J.: Reasons for hardness in QBF proof systems. In: FSTTCS. LIPIcs, vol. 93, pp. 14:1–14:15. Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik (2017)Google Scholar
- 10.Biere, A.: Resolve and expand. In: Hoos, H.H., Mitchell, D.G. (eds.) SAT 2004. LNCS, vol. 3542, pp. 59–70. Springer, Heidelberg (2005). https://doi.org/10.1007/11527695_5CrossRefzbMATHGoogle Scholar
- 11.Bogaerts, B., Janhunen, T., Tasharrofi, S.: SAT-to-SAT in QBFEval 2016. In: QBF Workshop, CEUR Workshop Proceedings, vol. 1719, pp. 63–70. CEUR-WS.org (2016)Google Scholar
- 12.Bogaerts, B., Janhunen, T., Tasharrofi, S.: Solving QBF instances with nested SAT solvers. In: Beyond NP Workshop 2016 at AAAI 2016 (2016)Google Scholar
- 13.Bordeaux, L., Cadoli, M., Mancini, T.: CSP properties for quantified constraints: definitions and complexity. In: AAAI, pp. 360–365. AAAI Press/The MIT Press (2005)Google Scholar
- 14.Cadoli, M., Giovanardi, A., Schaerf, M.: An algorithm to evaluate quantified Boolean formulae. In: AAAI, pp. 262–267. AAAI Press/The MIT Press (1998)Google Scholar
- 15.Charwat, G., Woltran, S.: Expansion-based QBF solving on tree decompositions. In: RCRA Workshop, CEUR Workshop Proceedings, vol. 2011, pp. 16–26. CEUR-WS.org (2017)Google Scholar
- 16.Chen, H.: A rendezvous of logic, complexity, and algebra. ACM Comput. Surv. 42(1), 2:1–2:32 (2009)CrossRefGoogle Scholar
- 17.Chen, H.: Meditations on quantified constraint satisfaction. In: Constable, R.L., Silva, A. (eds.) Logic and Program Semantics. LNCS, vol. 7230, pp. 35–49. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-29485-3_4CrossRefGoogle Scholar
- 18.Chen, H.: Proof complexity modulo the polynomial hierarchy: understanding alternation as a source of hardness. TOCT 9(3), 15:1–15:20 (2017)MathSciNetGoogle Scholar
- 19.Clarke, E.M., Grumberg, O., Jha, S., Lu, Y., Veith, H.: Counterexample-guided abstraction refinement for symbolic model checking. J. ACM 50(5), 752–794 (2003)MathSciNetCrossRefGoogle Scholar
- 20.Cook, S.A., Reckhow, R.A.: The relative efficiency of propositional proof systems. J. Symb. Log. 44(1), 36–50 (1979)MathSciNetCrossRefGoogle Scholar
- 21.Davis, M., Logemann, G., Loveland, D.W.: A machine program for theorem-proving. Commun. ACM 5(7), 394–397 (1962)MathSciNetCrossRefGoogle Scholar
- 22.Egly, U., Seidl, M., Tompits, H., Woltran, S., Zolda, M.: Comparing different prenexing strategies for quantified Boolean formulas. In: Giunchiglia, E., Tacchella, A. (eds.) SAT 2003. LNCS, vol. 2919, pp. 214–228. Springer, Heidelberg (2004). https://doi.org/10.1007/978-3-540-24605-3_17CrossRefGoogle Scholar
- 23.Giunchiglia, E., Narizzano, M., Pulina, L., Tacchella, A.: Quantified Boolean Formulas Library (QBFLIB) and Solver Evaluation Portal (QBFEVAL) (2004). www.qbflib.org
- 24.Giunchiglia, E., Narizzano, M., Tacchella, A.: Learning for quantified boolean logic satisfiability. In: AAAI, pp. 649–654. AAAI Press/The MIT Press (2002)Google Scholar
- 25.Giunchiglia, E., Narizzano, M., Tacchella, A.: Clause/term resolution and learning in the evaluation of quantified Boolean formulas. JAIR 26, 371–416 (2006)MathSciNetCrossRefGoogle Scholar
- 26.Heule, M., Järvisalo, M., Lonsing, F., Seidl, M., Biere, A.: Clause elimination for SAT and QSAT. JAIR 53, 127–168 (2015)MathSciNetCrossRefGoogle Scholar
- 27.Hooker, J.N.: Testing heuristics: we have it all wrong. J. Heuristics 1(1), 33–42 (1995)CrossRefGoogle Scholar
- 28.Janota, M.: Towards generalization in QBF solving via machine learning. In: Proceedings of the AAAI 2018 (2018, to appear)Google Scholar
- 29.Janota, M., Jordan, C., Klieber, W., Lonsing, F., Seidl, M., Van Gelder, A.: The QBFGallery 2014: the QBF competition at the FLoC olympic games. JSAT 9, 187–206 (2016)Google Scholar
- 30.Janota, M., Klieber, W., Marques-Silva, J., Clarke, E.: Solving QBF with counterexample guided refinement. Artif. Intell. 234, 1–25 (2016)MathSciNetCrossRefGoogle Scholar
- 31.Janota, M., Marques-Silva, J.: Expansion-based QBF solving versus Q-resolution. Theor. Comput. Sci. 577, 25–42 (2015)MathSciNetCrossRefGoogle Scholar
- 32.Janota, M., Marques-Silva, J.: Solving QBF by clause selection. In: IJCAI, pp. 325–331. AAAI Press (2015)Google Scholar
- 33.Kleine Büning, H., Bubeck, U.: Theory of quantified Boolean formulas. In: Handbook of Satisfiability, FAIA, vol. 185, pp. 735–760. IOS Press (2009)Google Scholar
- 34.Kleine Büning, H., Karpinski, M., Flögel, A.: Resolution for quantified Boolean formulas. Inf. Comput. 117(1), 12–18 (1995)MathSciNetCrossRefGoogle Scholar
- 35.Klieber, W., Sapra, S., Gao, S., Clarke, E.: A non-prenex, non-clausal QBF solver with game-state learning. In: Strichman, O., Szeider, S. (eds.) SAT 2010. LNCS, vol. 6175, pp. 128–142. Springer, Heidelberg (2010). https://doi.org/10.1007/978-3-642-14186-7_12CrossRefGoogle Scholar
- 36.Letz, R.: Lemma and model caching in decision procedures for quantified Boolean formulas. In: Egly, U., Fermüller, C.G. (eds.) TABLEAUX 2002. LNCS (LNAI), vol. 2381, pp. 160–175. Springer, Heidelberg (2002). https://doi.org/10.1007/3-540-45616-3_12CrossRefzbMATHGoogle Scholar
- 37.Lonsing, F., Egly, U.: DepQBF 6.0: a search-based QBF solver beyond traditional QCDCL. In: de Moura, L. (ed.) CADE 2017. LNCS (LNAI), vol. 10395, pp. 371–384. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-63046-5_23CrossRefGoogle Scholar
- 38.Lonsing, F., Egly, U.: Evaluating QBF solvers: quantifier alternations matter. CoRR abs/1701.06612 (2018). http://arxiv.org/abs/1701.06612, CP 2018 proceedings version with appendix
- 39.Lonsing, F., Seidl, M., Van Gelder, A.: The QBF gallery: behind the scenes. Artif. Intell. 237, 92–114 (2016)MathSciNetCrossRefGoogle Scholar
- 40.Marin, P., Narizzano, M., Pulina, L., Tacchella, A., Giunchiglia, E.: Twelve years of QBF evaluations: QSAT is PSPACE-hard and it shows. Fundam. Inf. 149(1–2), 133–158 (2016)MathSciNetCrossRefGoogle Scholar
- 41.Martin, B.: Quantified constraints in twenty seventeen. In: The Constraint Satisfaction Problem: Complexity and Approximability, Dagstuhl Follow-Ups, vol. 7, pp. 327–346. Schloss Dagstuhl - Leibniz-Zentrum fuer Informatik (2017)Google Scholar
- 42.Meyer, A.R., Stockmeyer, L.J.: The equivalence problem for regular expressions with squaring requires exponential space. In: 13th Annual Symposium on Switching and Automata Theory, pp. 125–129. IEEE Computer Society (1972)Google Scholar
- 43.Peitl, T., Slivovsky, F., Szeider, S.: Dependency learning for QBF. In: Gaspers, S., Walsh, T. (eds.) SAT 2017. LNCS, vol. 10491, pp. 298–313. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-66263-3_19CrossRefGoogle Scholar
- 44.Pulina, L., Seidl, M.: QBFEVAL’17: competitive evaluation of QBF solvers (2017). http://www.qbflib.org/event_page.php?year=2017
- 45.Pulina, L., Tacchella, A.: Treewidth: a useful marker of empirical hardness in quantified Boolean Logic Encodings. In: Cervesato, I., Veith, H., Voronkov, A. (eds.) LPAR 2008. LNCS (LNAI), vol. 5330, pp. 528–542. Springer, Heidelberg (2008). https://doi.org/10.1007/978-3-540-89439-1_37CrossRefzbMATHGoogle Scholar
- 46.Rabe, M.N., Tentrup, L.: CAQE: a certifying QBF solver. In: FMCAD, pp. 136–143. IEEE (2015)Google Scholar
- 47.Silva, J.P.M., Lynce, I., Malik, S.: Conflict-driven clause learning SAT solvers. In: Handbook of Satisfiability, FAIA, vol. 185, pp. 131–153. IOS Press (2009)Google Scholar
- 48.Stockmeyer, L.J.: The polynomial-time hierarchy. Theor. Comput. Sci. 3(1), 1–22 (1976)MathSciNetCrossRefGoogle Scholar
- 49.Stockmeyer, L.J., Meyer, A.R.: Word problems requiring exponential time: preliminary report. In: STOC, pp. 1–9. ACM (1973)Google Scholar
- 50.Tentrup, L.: On expansion and resolution in CEGAR based QBF solving. In: Majumdar, R., Kunčak, V. (eds.) CAV 2017. LNCS, vol. 10427, pp. 475–494. Springer, Cham (2017). https://doi.org/10.1007/978-3-319-63390-9_25CrossRefGoogle Scholar
- 51.Tseitin, G.S.: On the complexity of derivation in propositional calculus. Stud. Constr. Math. Math. Log., 115–125 (1968)Google Scholar
- 52.Wimmer, R., Reimer, S., Marin, P., Becker, B.: HQSpre – an effective preprocessor for QBF and DQBF. In: Legay, A., Margaria, T. (eds.) TACAS 2017. LNCS, vol. 10205, pp. 373–390. Springer, Heidelberg (2017). https://doi.org/10.1007/978-3-662-54577-5_21CrossRefGoogle Scholar
- 53.Wrathall, C.: Complete sets and the polynomial-time hierarchy. Theor. Comput. Sci. 3(1), 23–33 (1976)MathSciNetCrossRefGoogle Scholar
- 54.Xu, L., Hutter, F., Hoos, H., Leyton-Brown, K.: Evaluating component solver contributions to portfolio-based algorithm selectors. In: Cimatti, A., Sebastiani, R. (eds.) SAT 2012. LNCS, vol. 7317, pp. 228–241. Springer, Heidelberg (2012). https://doi.org/10.1007/978-3-642-31612-8_18CrossRefGoogle Scholar
- 55.Zhang, L., Malik, S.: Towards a symmetric treatment of satisfaction and conflicts in quantified Boolean formula evaluation. In: Van Hentenryck, P. (ed.) CP 2002. LNCS, vol. 2470, pp. 200–215. Springer, Heidelberg (2002). https://doi.org/10.1007/3-540-46135-3_14CrossRefGoogle Scholar