Abstract
Research on the constraint satisfaction problem (CSP) is an active field both in theory and practice. An extension of CSP even considers universal and existential quantification of domain variables, known as QCSP, for which also solvers exist. The number of alternations between existential and universal quantifications is usually called quantifier rank. While QCSP is PSPACE-complete for bounded domain size, one can consider additional structural restrictions that make the problem tractable, for example, bounded treewidth. Chen [14] showed that one can solve QCSP instances of size n, quantifier rank \(\ell \), bounded treewidth k, and bounded domain size d in \(\text {poly}(n)\cdot \text {tower}(\ell -1,d^k)\), where tower are exponentials of height \(\ell -1\) with \(d^k\) on top. We follow up on Chen’s result and develop a treewidth-aware quantifier elimination technique that reduces the rank without an exponential blow-up in the instance size at the cost of exponentially increasing the treewidth. With this reduction at hand we show that one cannot significantly improve the blow-up of the treewidth assuming the exponential time hypothesis (ETH). Further, we lift a recently introduced technique for treewidth-decreasing quantifier expansion from the Boolean domain to QCSP.
The work has been supported by the Austrian Science Fund (FWF), Grants Y698 and P32830, and the Vienna Science and Technology Fund, Grant WWTF ICT19-065. We would like to thank the anonymous reviewers for very detailed feedback and their suggestions. Special appreciation goes to Andreas Pfandler for early discussions.
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Notes
- 1.
\(\mathsf {tower}(\ell ,x)\) is a tower of iterated exponentials of 2 of height \(\ell \) with x on top.
References
Allouche, D., et al.: Tractability-preserving transformations of global cost functions. Artif. Intell. 238, 166–189 (2016)
Atserias, A., Fichte, J.K., Thurley, M.: Clause-learning algorithms with many restarts and bounded-width resolution. J. Artif. Intell. Res. 40, 353–373 (2011)
Atserias, A., Oliva, S.: Bounded-width QBF is PSPACE-complete. J. Comput. Syst. Sci. 80(7), 1415–1429 (2014)
Bacchus, F., Stergiou, K.: Solution directed backjumping for QCSP. In: Bessière, C. (ed.) CP 2007. LNCS, vol. 4741, pp. 148–163. Springer, Heidelberg (2007). https://doi.org/10.1007/978-3-540-74970-7_13
Beldiceanu, N., Demassey, S.: Global Constraint Catalog: 5.117. element (2020). https://web.imt-atlantique.fr/x-info/sdemasse/gccat/Celement.html
Benedetti, M., Lallouet, A., Vautard, J.: QCSP made practical by virtue of restricted quantification. In: IJCAI, pp. 38–43 (2007)
Bertelè, U., Brioschi, F.: Contribution to nonserial dynamic programming. J. Math. Anal. Appl. 28(2), 313–325 (1969)
Bertelè, U., Brioschi, F.: Nonserial Dynamic Programming. Academic Press Inc., Cambridge (1972)
Bertelè, U., Brioschi, F.: On Non-serial dynamic programming. J. Comb. Theory Ser. A 14(2), 137–148 (1973)
Bodlaender, H.L.: A linear-time algorithm for finding tree-decompositions of small treewidth. SIAM J. Comput. 25(6), 1305–1317 (1996)
Bodlaender, H.L.: A partial k-arboretum of graphs with bounded treewidth. Theoret. Comput. Sci. 209(1–2), 1–45 (1998)
Bondy, J.A., Murty, U.: Graph Theory. Graduate Texts in Mathematics, vol. 244. Springer, Heidelberg (2008)
Charwat, G., Woltran, S.: Expansion-based QBF solving on tree decompositions. Fundamenta Informaticae 167(1–2), 59–92 (2019)
Chen, H.: Quantified constraint satisfaction and bounded treewidth. In: Proceedings of the 16th European Conference on Artificial Intelligence (ECAI 2004), vol. IOS Press, pp. 161–170 (2004)
Creignou, N., Vollmer, H.: Boolean constraint satisfaction problems: when does Post’s lattice help? In: Creignou, N., Kolaitis, P.G., Vollmer, H. (eds.) Complexity of Constraints. LNCS, vol. 5250, pp. 3–37. Springer, Heidelberg (2008). https://doi.org/10.1007/978-3-540-92800-3_2
Cygan, M., et al.: Parameterized Algorithms. Springer, Heidelberg (2015). https://doi.org/10.1007/978-3-319-21275-3
Dechter, R.: Tractable structures for constraint satisfaction problems. In: Handbook of Constraint Programming, vol. I, pp. 209–244. Elsevier (2006). (Chap. 7)
Diestel, R.: Graph Theory. Graduate Texts in Mathematics, vol. 173, 4th edn. Springer, Heidelberg (2012)
Downey, R.G., Fellows, M.R.: Fundamentals of Parameterized Complexity. TCS. Springer, London (2013). https://doi.org/10.1007/978-1-4471-5559-1
Dvořák, W., Pichler, R., Woltran, S.: Towards fixed-parameter tractable algorithms for abstract argumentation. Artif. Intell. 186, 1–37 (2012)
Ferguson, A., O’Sullivan, B.: Quantified constraint satisfaction problems: from relaxations to explanations. In: Proceedings of the Twenty-Sixth International Joint Conference on Artificial Intelligence (IJCAI 2007), pp. 74–79. The AAAI Press (2007)
Fichte, J.K., Hecher, M., Morak, M., Woltran, S.: DynASP2.5: dynamic programming on tree decompositions in action. In: Lokshtanov, D., Nishimura, N. (eds.) Proceedings of the 12th International Symposium on Parameterized and Exact Computation (IPEC 2017). Dagstuhl Publishing (2017)
Fichte, J.K., Hecher, M., Pfandler, A.: Lower bounds for QBFs of bounded treewidth. In: Kobayashi, N. (ed.) Proceedings of the 35th Annual ACM/IEEE Symposium on Logic in Computer Science (LICS 2020), pp. 410–424. ACM (2020)
Fichte, J.K., Hecher, M., Thier, P., Woltran, S.: Exploiting database management systems and treewidth for counting. In: Komendantskaya, E., Liu, Y.A. (eds.) PADL 2020. LNCS, vol. 12007, pp. 151–167. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-39197-3_10
Fichte, J.K., Hecher, M., Zisser, M.: An improved GPU-based SAT model counter. In: Schiex, T., de Givry, S. (eds.) CP 2019. LNCS, vol. 11802, pp. 491–509. Springer, Cham (2019). https://doi.org/10.1007/978-3-030-30048-7_29
Fichte, J.K., Hecher, M., Woltran, S., Zisser, M.: Weighted model counting on the GPU by exploiting small treewidth. In: Azar, Y., Bast, H., Herman, G. (eds.) Proceedings of the 26th Annual European Symposium on Algorithms (ESA 2018). LIPIcs, vol. 112, pp. 28:1–28:16. Dagstuhl Publishing (2018)
Flum, J., Grohe, M.: Parameterized Complexity Theory. TTCSAES. Springer, Heidelberg (2006). https://doi.org/10.1007/3-540-29953-X
Freuder, E.C.: A sufficient condition for backtrack-bounded search. J. ACM 32(4), 755–761 (1985)
Gent, I.P., Nightingale, P., Stergiou, K.: QCSP-solve: a solver for quantified constraint satisfaction problems. In: IJCAI, pp. 138–143. Professional Book Center (2005)
Godet, A., Lorca, X., Hebrard, E., Simonin, G.: Using approximation within constraint programming to solve the parallel machine scheduling problem with additional unit resources. In: Conitzer, V., Sha, F. (eds.) Proceedings of the 34th AAAI Conference on Artificial Intelligence. The AAAI Press, New York (2020)
Gottlob, G., Greco, G., Scarcello, F.: The complexity of quantified constraint satisfaction problems under structural restrictions. In: IJCAI, pp. 150–155. Professional Book Center (2005)
Gottlob, G., Pichler, R., Wei, F.: Bounded treewidth as a key to tractability of knowledge representation and reasoning. Artif. Intell. 174(1), 105–132 (2010)
Hecher, M., Fichte, J.K., Kieler, M.F.I.: Supplemental material of this submission, containing proofs of theorems marked with “\(\star \)” (2020). Self-archived copy by the authors available online
Hecher, M., Thier, P., Woltran, S.: Taming high treewidth with abstraction, nested dynamic programming, and database technology. In: Pulina, L., Seidl, M. (eds.) SAT 2020. LNCS, vol. 12178, pp. 343–360. Springer, Cham (2020). https://doi.org/10.1007/978-3-030-51825-7_25
Hemaspaandra, E.: Dichotomy theorems for alternation-bounded quantified Boolean formulas. CoRR cs.CC/0406006 (2004). http://arxiv.org/abs/cs/0406006
Hooker, J.N., van Hoeve, W.-J.: Constraint programming and operations research. Constraints 23(2), 172–195 (2017). https://doi.org/10.1007/s10601-017-9280-3
Impagliazzo, R., Paturi, R., Zane, F.: Which problems have strongly exponential complexity? J. Comput. Syst. Sci. 63(4), 512–530 (2001)
Jégou, P., Terrioux, C.: Hybrid backtracking bounded by tree-decomposition of constraint networks. Artif. Intell. 146(1), 43–75 (2003)
Karp, R.M.: Reducibility among combinatorial problems. In: Complexity of Computer Computations. The IBM Research Symposia Series, pp. 85–103. Plenum Press, New York (1972)
Kloks, T. (ed.): Treewidth: Computations and Approximations. LNCS, vol. 842. Springer, Heidelberg (1994). https://doi.org/10.1007/BFb0045375
Kuo, C., Ravi, S.S., Dao, T., Vrain, C., Davidson, I.: A framework for minimal clustering modification via constraint programming. In: Singh, S.P., Markovitch, S. (eds.) Proceedings of the 31st AAAI Conference on Artificial Intelligence, pp. 1389–1395. The AAAI Press, San Francisco (2017)
Lampis, M., Mitsou, V.: Treewidth with a quantifier alternation revisited. In: Proceedings of the 12th International Symposium on Parameterized and Exact Computation (IPEC 2017). LIPIcs, vol. 89, pp. 26:1–26:12. Dagstuhl Publishing (2017)
Ordyniak, S., Szeider, S.: Parameterized complexity results for exact Bayesian network structure learning. J. Artif. Intell. Res. 46, 263–302 (2013)
Otten, L., Dechter, R.: Anytime AND/OR depth-first search for combinatorial optimization. AI Commun. 25(3), 211–227 (2012)
Pan, G., Vardi, M.Y.: Fixed-parameter hierarchies inside PSPACE. In: LICS, pp. 27–36. IEEE Computer Society (2006)
Papadimitriou, C.H.: Computational Complexity. Addison-Wesley, Boston (1994)
Pichler, R., Rümmele, S., Woltran, S.: Counting and enumeration problems with bounded treewidth. In: Clarke, E.M., Voronkov, A. (eds.) LPAR 2010. LNCS (LNAI), vol. 6355, pp. 387–404. Springer, Heidelberg (2010). https://doi.org/10.1007/978-3-642-17511-4_22
Robertson, N., Seymour, P.: Graph minors. I. Excluding a forest. J. Comb. Theory Ser. B 35(1), 39–61 (1983)
Samer, M., Szeider, S.: Algorithms for propositional model counting. J. Discrete Algorithms 8(1), 50–64 (2010)
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Fichte, J.K., Hecher, M., Kieler, M.F.I. (2020). Treewidth-Aware Quantifier Elimination and Expansion for QCSP. In: Simonis, H. (eds) Principles and Practice of Constraint Programming. CP 2020. Lecture Notes in Computer Science(), vol 12333. Springer, Cham. https://doi.org/10.1007/978-3-030-58475-7_15
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