Abstract
We study the hardness of approximation of clause minimum and literal minimum representations of pure Horn functions in n Boolean variables. We show that unless P=NP, it is not possible to approximate in polynomial time the minimum number of clauses and the minimum number of literals of pure Horn CNF representations to within a factor of \(2^{\log^{1-o(1)} n}\). This is the case even when the inputs are restricted to pure Horn 3-CNFs with O(n 1+ε) clauses, for some small positive constant ε. Furthermore, we show that even allowing sub-exponential time computation, it is still not possible to obtain constant factor approximations for such problems unless the Exponential Time Hypothesis turns out to be false.
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Arora, S., Barak, B.: Computational Complexity: A modern approach. Cambridge University Press. xxiv+579. ISBN: 978-0-521-42426-4 (2009)
Arora, S., Babai, L., Stern, J., Sweedyk, Z.: The hardness of approximate optima in lattices, codes, and systems of linear equations. J. Comput. Syst. Sci. 54(2, part 2), 317–331 (1997). doi:10.1006/jcss.1997.1472
Arora, S., Lund, C.: Hardness of approximations. In: Hochbaum, D. (ed.) Approximation Algorithms for NP-Hard Problems. PWS Publishing, Boston (1996)
Arora, S., Lund, C., Motwani, R., Sudan, M., Szegedy, M.: Proof verification and the hardness of approximation problems. J. ACM 45(3), 501–555 (1998). doi:10.1145/278298.278306
Arora, S., Safra, S.: Probabilistic checking of proofs: A new characterization of NP. J. ACM 45(1), 70–122 (1998). doi:10.1145/273865.273901
Ausiello, G., D’Atri, A., Saccà, D.: Minimal representation of directed hypergraphs. SIAM J. Comput. 15(2), 418–431 (1986). doi:10.1137/0215029
Bhattacharya, A., DasGupta, B., Mubayi, D., Turán, G.: On approximate Horn formula minimization. In: Abramsky, S., Gavoille, C., Kirchner, C., auf der Heide, F.M., Spirakis, P.G. (eds.) ICALP (1), Lecture Notes in Computer Science, vol. 6198, pp. 438–450. Springer (2010)
Boros, E., Ċepek, O., Kuċera, P.: A decomposition method for CNF minimality proofs. Theor. Comput. Sci. 510, 111–126 (2013). doi:10.1016/j.tcs.2013.09.016
Boros, E., Ċepek, O., Kogan, A., Kuċera, P.: Exclusive and essential sets of implicates of Boolean functions. Discret. Appl. Math. 158(2), 81–96 (2010). doi:10.1016/j.dam.2009.08.012
Boros, E., Gruber, A.: Hardness results for approximate pure Horn CNF formulae minimization. In: International Symposium on Artificial Intelligence and Mathematics (ISAIM 2012), Fort Lauderdale, Florida, USA, January 9-11 (2012)
Cook, S.A.: The complexity of theorem-proving procedures. In: Proceedings of the 3rd Annual ACM Symposium on Theory of Computing (STOC). pp. 151-158. Ohio. doi:10.1145/800157.805047 (1971)
Crama, Y., Hammer, P.L. (eds.): Boolean Functions: Theory, Algorithms, and Applications. Encyclopedia of Mathematics and its Applications, vol. 142. Cambridge University Press, Cambridge (2011)
Cormen, T. H., Leiserson, C. E., Rivest, R.L., Stein, C.: Introduction to algorithms, 3rd edn, pp. xx+1292. MIT Press, Cambridge. ISBN 978-0-262-03384-8 (2009)
Dinur, I., Harsha, P.: Composition of low-error 2-query PCPs using decodable PCPs. SIAM J. Comput. 42(6), 2452–2486 (2013). doi:10.1137/100788161
Dinur, I., Safra, S.: On the hardness of approximating label-cover. Inf. Process. Lett. 89(5), 247–254 (2004). doi:10.1016/j.ipl.2003.11.007
Dowling, W.F., Gallier, J.H.: Linear-time algorithms for testing the satisfiability of propositional Horn formulae. J. Log. Prog. 1(3), 267–284 (1984). doi:10.1016/0743-1066(84)90014-1
Feige, U., Goldwasser, S., Lovász, L., Safra, S., Szegedy, M.: Interactive proofs and the hardness of approximating cliques. J. ACM 43(2), 268–292 (1996). doi:10.1145/226643.226652
Feige, U., Lovász, L.: Two-prover one-round proof systems: Their power and their problems (extended abstract). STOC, pp. 733–744. ACM (1992)
Garey, M.R., Johnson, D.S. Computers and intractability. W. H. Freeman and Co., San Francisco. A guide to the theory of NP-completeness, A Series of Books in the Mathematical Sciences (1979)
Hammer, P.L., Kogan, A.: Horn functions and their DNFs. Inf. Process. Lett. 44(1), 23–29 (1992). doi:10.1016/0020-0190(92)90250-Y
Hammer, P.L., Kogan, A.: Optimal compression of propositional Horn knowledge bases: complexity and approximation. Artif. Intell. 64(1), 131–145 (1993). doi:10.1016/0004-3702(93)90062-G
Impagliazzo, R., Paturi, R.: On the complexity of k-SAT. J. Comput. Syst. Sci. 62(2), 367–375 (2001). doi:10.1006/jcss.2000.1727. Special issue on the fourteenth annual IEEE conference on computational complexity (Atlanta, GA, 1999)
Itai, A., Makowsky, J.A.: Unification as a complexity measure for logic programming. J. Log. Prog. 4(2), 105–117 (1987). doi:10.1016/0743-1066(87)90014-8
Kortsarz, G.: On the hardness of approximating spanners. Algorithmica 30(3), 432–450 (2001). Approximation algorithms for combinatorial optimization problems
Maier, D.: Minimum covers in relational database model. J. ACM 27(4), 664–674 (1980). doi:10.1145/322217.322223
Minoux, M.: Ltur: A simplified linear-time unit resolution algorithm for Horn formulae and computer implementation. Inf. Process. Lett. 29(1), 1–12 (1988). doi:10.1016/0020-0190(88)90124-X
Moshkovitz, D., Raz, R.: Two-query PCP with subconstant error. J. ACM 57(5), Art, 29, 29 (2010). doi:10.1145/1.754399.1754402
Umans, C.: Hardness of approximating \({\Sigma ^{p}_{2}}\) minimization problems. In: 40th Annual Symposium on Foundations of Computer Science (New York, 1999), pp. 465–474, IEEE Computer Soc., Los Alamitos. doi:10.1109/SFFCS.1999.814619 (1999)
Vazirani, V.V.: Approximation Algorithms. Springer (2001)
Williamson, D.P., Shmoys, D.B.: The Design of Approximation Algorithms. Cambridge University Press, Cambridge (2011)
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The authors gratefully acknowledge the partial support by NSF grants IIS 0803444 and by CMMI 0856663. The second author also gratefully acknowledge the partial support by the joint CAPES (Brazil)/Fulbright (USA) fellowship process BEX-2387050/15061676.
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Boros, E., Gruber, A. Hardness results for approximate pure Horn CNF formulae minimization. Ann Math Artif Intell 71, 327–363 (2014). https://doi.org/10.1007/s10472-014-9415-9
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DOI: https://doi.org/10.1007/s10472-014-9415-9
Keywords
- Boolean functions
- Propositional Horn logic
- Hardness of approximation
- Computational complexity
- Artificial intelligence