Abstract

The constraint satisfaction problem (CSP) is concerned with homomorphisms between two structures. For CSPs with restricted left-hand-side structures, the results of Dalmau, Kolaitis, and Vardi [Proceedings of the 8th International Conference on Principles and Practice of Constraint Programming, Springer, New York, 2002, pp. 310--326], Grohe [J. ACM, 54 (2007), 1], and Atserias, Bulatov, and Dalmau [Proceedings of the 34th International Colloquium on Automata, Languages and Programming, Springer, New York, 2007, pp. 279--290] establish the precise borderline of polynomial-time solvability (subject to complexity-theoretic assumptions) and of solvability by bounded-consistency algorithms (unconditionally) as bounded treewidth modulo homomorphic equivalence. The general-valued constraint satisfaction problem (VCSP) is a generalization of the CSP concerned with homomorphisms between two valued structures. For VCSPs with restricted left-hand-side valued structures, we establish the precise borderline of polynomial-time solvability (subject to complexity-theoretic assumptions) and of solvability by the $k$th level of the Sherali--Adams LP hierarchy (unconditionally). We also obtain results on related problems concerned with finding a solution and recognizing the tractable cases; the latter has an application in database theory.

Keywords

  1. valued constraint satisfaction
  2. homomorphism problems
  3. fractional homomorphism
  4. treewidth
  5. Sherali--Adams LP relaxation

MSC codes

  1. 68Q25
  2. 68R01
  3. 03B70
  4. 90C05

Get full access to this article

View all available purchase options and get full access to this article.

References

1.
A. Atserias, A. A. Bulatov, and V. Dalmau, On the power of k-consistency, in Proceedings of the 34th International Colloquium on Automata, Languages and Programming, Lecture Notes in Comput. Sci. 4596, Springer, New York, 2007, pp. 279--290, https://doi.org/10.1007/978-3-540-73420-8_26.
2.
L. Barto and M. Kozik, Constraint satisfaction problems solvable by local consistency methods, J. ACM, 61 (2014), 3, https://doi.org/10.1145/2556646.
3.
L. Barto, M. Kozik, and T. Niven, The CSP dichotomy holds for digraphs with no sources and no sinks (a positive answer to a conjecture of Bang-Jensen and Hell), SIAM J. Comput., 38 (2009), pp. 1782--1802, https://doi.org/10.1137/070708093.
4.
U. Bertelé and F. Brioschi, Nonserial Dynamic Programming, Academic Press, New York, 1972.
5.
D. Bienstock and N. Özbay, Tree-width and the Sherali-Adams operator, Discrete Optim., 1 (2004), pp. 13--21, https://doi.org/10.1016/j.disopt.2004.03.002.
6.
H. L. Bodlaender, A linear-time algorithm for finding tree-decompositions of small treewidth, SIAM J. Comput., 25 (1996), pp. 1305--1317, https://doi.org/10.1137/S0097539793251219.
7.
A. Bulatov, A dichotomy theorem for constraint satisfaction problems on a 3-element set, J. ACM, 53 (2006), pp. 66--120, https://doi.org/10.1145/1120582.1120584.
8.
A. Bulatov, A dichotomy theorem for nonuniform CSPs, in Proceedings of the 58th Annual IEEE Symposium on Foundations of Computer Science, IEEE, 2017, pp. 319--330.
9.
A. Bulatov, V. Dalmau, M. Grohe, and D. Marx, Enumerating homomorphisms, J. Comput. System Sci., 78 (2012), pp. 638--650.
10.
A. Bulatov, P. Jeavons, and A. Krokhin, Classifying the complexity of constraints using finite algebras, SIAM J. Comput., 34 (2005), pp. 720--742, https://doi.org/10.1137/S0097539700376676.
11.
A. A. Bulatov, Complexity of conservative constraint satisfaction problems, ACM Trans. Comput. Logic, 12 (2011), 24, https://doi.org/10.1145/1970398.1970400.
12.
C. Carbonnel, M. Romero, and S. Živný, The complexity of general-valued CSPs seen from the other side, in Proceedings of the 59th Annual IEEE Symposium on Foundations of Computer Science, IEEE, 2018, pp. 236--246, https://doi.org/10.1109/FOCS.2018.00031.
13.
A. K. Chandra and P. M. Merlin, Optimal implementation of conjunctive queries in relational data bases, in Proceedings of the 9th Annual ACM Symposium on Theory of Computing ACM, 1977, pp. 77--90, https://doi.org/10.1145/800105.803397.
14.
H. Chen and S. Mengel, A trichotomy in the complexity of counting answers to conjunctive queries, in Proceedings of the 18th International Conference on Database Theory, 2015, pp. 110--126, https://doi.org/10.4230/LIPIcs.ICDT.2015.110.
15.
D. A. Cohen, M. C. Cooper, P. G. Jeavons, and A. A. Krokhin, The complexity of soft constraint satisfaction, Artificial Intelligence, 170 (2006), pp. 983--1016, https://doi.org/10.1016/j.artint.2006.04.002.
16.
V. Dalmau, P. G. Kolaitis, and M. Y. Vardi, Constraint satisfaction, bounded treewidth, and finite-variable logics, in Proceedings of the 8th International Conference on Principles and Practice of Constraint Programming, Lecture Notes in Comput. Sci. 2470, Springer, New York, 2002, pp. 310--326, https://doi.org/10.1007/3-540-46135-3_21.
17.
R. Dechter, Constraint Processing, Morgan Kaufmann, Burlington, MA, 2003.
18.
R. Diestel, Graph Theory, 4th ed., Springer, New York, 2010.
19.
R. G. Downey and M. R. Fellows, Fixed-parameter tractability and completeness I: Basic results, SIAM J. Comput., 24 (1995), pp. 873--921, https://doi.org/10.1137/S0097539792228228.
20.
R. G. Downey and M. R. Fellows, Fixed-parameter tractability and completeness II: On completeness for W[1], Theoret. Comput. Sci., 141 (1995), pp. 109--131.
21.
T. Färnqvist, Constraint optimization problems and bounded tree-width revisited, in Proceedings of the 9th International Conference on Integration of Artificial Intelligence and Operations Research Techniques in Constraint Programming, Lecture Notes in Comput. Sci. 7298, Springer, New York, 2012, pp. 163--197, https://doi.org/10.1007/978-3-642-29828-8_11.
22.
T. Färnqvist, Exploiting Structure in CSP-related Problems, Ph.D. thesis, Department of Computer Science and Information Science, Linköping University, 2013.
23.
T. Färnqvist and P. Jonsson, Bounded tree-width and CSP-related problems, in Proceedings of the 18th International Symposium on Algorithms and Computation, Lecture Notes in Comput. Sci. 4835, Springer, New York, 2007, pp. 632--643, https://doi.org/10.1007/978-3-540-77120-3_55.
24.
T. Feder and M. Y. Vardi, The computational structure of monotone monadic SNP and constraint satisfaction: A study through datalog and group theory, SIAM J. Comput., 28 (1998), pp. 57--104, https://doi.org/10.1137/S0097539794266766.
25.
J. Flum and M. Grohe, Parameterized Complexity Theory, Springer, New York, 2006.
26.
E. C. Freuder, A sufficient condition for backtrack-free search, J. ACM, 29 (1982), pp. 24--32.
27.
E. C. Freuder, Complexity of K-tree structured constraint satisfaction problems, in Proceedings of the 8th National Conference on Artificial Intelligence, 1990, pp. 4--9.
28.
G. Gottlob, G. Greco, N. Leone, and F. Scarcello, Hypertree decompositions: Questions and answers, in Proceedings of the 35th SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, 2016, pp. 57--74.
29.
G. Gottlob, G. Greco, and F. Scarcello, Tractable optimization problems through hypergraph-based structural restrictions, in Proceedings of the 36th International Colloquium on Automata, Languages and Programming, Part II, Lecture Notes in Comput. Sci. 5556, Springer, New York, 2009, pp. 16--30, https://doi.org/10.1007/978-3-642-02930-1_2.
30.
T. J. Green, Containment of conjunctive queries on annotated relations, Theory Comput. Syst., 49 (2011), pp. 429--459.
31.
T. J. Green and V. Tannen, The semiring framework for database provenance, in Proceedings of the 36th SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, 2017, pp. 93--99.
32.
M. Grohe, The complexity of homomorphism and constraint satisfaction problems seen from the other side, J. ACM, 54 (2007), 1, https://doi.org/10.1145/1206035.1206036.
33.
M. Grötschel, L. Lovász, and A. Schrijver, Geometric Algorithms and Combinatorial Optimization, Algorithms Combin. 2, Springer, New York, 1988.
34.
P. Hell and J. Nešetřil, The core of a graph, Discrete Math., 109 (1992), pp. 117--126, https://doi.org/https://doi.org/10.1016/0012-365X(92)90282-K.
35.
P. Hell and J. Nešetřil, Graphs and Homomorphisms, Oxford University Press, New York, 2004.
36.
P. M. Idziak, P. Markovic, R. McKenzie, M. Valeriote, and R. Willard, Tractability and learnability arising from algebras with few subpowers, SIAM J. Comput., 39 (2010), pp. 3023--3037, https://doi.org/10.1137/090775646.
37.
P. G. Kolaitis and M. Y. Vardi, Conjunctive-query containment and constraint satisfaction, in Proceedings of the 17th SIGACT-SIGMOD-SIGART Symposium on Principles of Database Systems, 1998, pp. 205--213, https://doi.org/10.1145/275487.275511.
38.
P. Kolman and M. Koutecký, Extended formulation for CSP that is compact for instances of bounded treewidth, Electron. J. Combin., 22 (2015), P4.30.
39.
V. Kolmogorov, A. A. Krokhin, and M. Rolínek, The complexity of general-valued CSPs, SIAM J. Comput., 46 (2017), pp. 1087--1110, https://doi.org/10.1137/16M1091836.
40.
E. V. Kostylev, J. L. Reutter, and A. Z. Salamon, Classification of annotation semirings over containment of conjunctive queries, ACM Trans. Database Syst., 39 (2014), 1, https://doi.org/10.1145/2556524.
41.
M. Kozik and J. Ochremiak, Algebraic properties of valued constraint satisfaction problem, in Proceedings of the 42nd International Colloquium on Automata, Languages and Programming, Lecture Notes in Comput. Sci. 9134, Springer, New York, 2015, pp. 846--858, https://doi.org/10.1007/978-3-662-47672-7_69.
42.
D. Marx, Tractable hypergraph properties for constraint satisfaction and conjunctive queries, J. ACM, 60 (2013), 42, https://doi.org/10.1145/2535926.
43.
U. Montanari, Networks of constraints: Fundamental properties and applications to picture processing, Inform. Sci., 7 (1974), pp. 95--132, https://doi.org/10.1016/0020-0255(74)90008-5.
44.
N. Robertson and P. D. Seymour, Graph minors. III. Planar tree-width, J. Combin. Theory Ser. B, 36 (1984), pp. 49--64, https://doi.org/10.1016/0095-8956(84)90013-3.
45.
N. Robertson and P. D. Seymour, Graph minors. V. Excluding a planar graph, J. Combin. Theory Ser. B, 41 (1986), pp. 92--114, https://doi.org/10.1016/0095-8956(86)90030-4.
46.
A. Schrijver, Theory of Linear and Integer Programming, John Wiley & Sons, New York, 1986.
47.
P. D. Seymour and R. Thomas, Graph searching and a min-max theorem for tree-width, J. Combin. Theory Ser. B, 58 (1993), pp. 22--33.
48.
H. D. Sherali and W. P. Adams, A hierarchy of relaxations between the continuous and convex hull representations for zero-one programming problems, SIAM J. Discrete Math., 3 (1990), pp. 411--430.
49.
J. Thapper and S. Živný, The power of linear programming for valued CSPs, in Proceedings of the 53rd Annual IEEE Symposium on Foundations of Computer Science, IEEE, 2012, pp. 669--678, https://doi.org/10.1109/FOCS.2012.25.
50.
J. Thapper and S. Živný, The complexity of finite-valued CSPs, J. ACM, 63 (2016), 37, https://doi.org/10.1145/2974019.
51.
J. Thapper and S. Živný, The power of Sherali-Adams relaxations for general-valued CSPs, SIAM J. Comput., 46 (2017), pp. 1241--1279, https://doi.org/10.1137/16M1079245.
52.
D. Zhuk, A proof of the CSP dichotomy conjecture, J. ACM, 67 (2020), 30, https://doi.org/10.1145/3402029.

Information & Authors

Information

Published In

cover image SIAM Journal on Computing
SIAM Journal on Computing
Pages: 19 - 69
ISSN (online): 1095-7111

History

Submitted: 15 March 2019
Accepted: 13 October 2021
Published online: 25 January 2022

Keywords

  1. valued constraint satisfaction
  2. homomorphism problems
  3. fractional homomorphism
  4. treewidth
  5. Sherali--Adams LP relaxation

MSC codes

  1. 68Q25
  2. 68R01
  3. 03B70
  4. 90C05

Authors

Affiliations

Funding Information

Horizon 2020 Framework Programme https://doi.org/10.13039/100010661

Funding Information

Fondo Nacional de Desarrollo Científico y Tecnológico https://doi.org/10.13039/501100002850

Funding Information

Royal Society https://doi.org/10.13039/501100000288

Metrics & Citations

Metrics

Citations

If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.

Cited By

Media

Figures

Other

Tables

Share

Share

Copy the content Link

Share with email

Email a colleague

Share on social media

The SIAM Publications Library now uses SIAM Single Sign-On for individuals. If you do not have existing SIAM credentials, create your SIAM account https://my.siam.org.