Skip to main content
Top
Published in: Journal of Automated Reasoning 2/2018

24-02-2017

Conflict Resolution: A First-Order Resolution Calculus with Decision Literals and Conflict-Driven Clause Learning

Authors: John Slaney, Bruno Woltzenlogel Paleo

Published in: Journal of Automated Reasoning | Issue 2/2018

Log in

Activate our intelligent search to find suitable subject content or patents.

search-config
loading …

Abstract

This paper defines the (first-order) conflict resolution calculus: an extension of the resolution calculus inspired by techniques used in modern Sat-solvers. The resolution inference rule is restricted to (first-order) unit propagation and the calculus is extended with a mechanism for assuming decision literals and with a new inference rule for clause learning, which is a first-order generalization of the propositional conflict-driven clause learning procedure. The calculus is sound (because it can be simulated by natural deduction) and refutationally complete (because it can simulate resolution), and these facts are proven in detail here.

Dont have a licence yet? Then find out more about our products and how to get one now:

Springer Professional "Wirtschaft+Technik"

Online-Abonnement

Mit Springer Professional "Wirtschaft+Technik" erhalten Sie Zugriff auf:

  • über 102.000 Bücher
  • über 537 Zeitschriften

aus folgenden Fachgebieten:

  • Automobil + Motoren
  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Elektrotechnik + Elektronik
  • Energie + Nachhaltigkeit
  • Finance + Banking
  • Management + Führung
  • Marketing + Vertrieb
  • Maschinenbau + Werkstoffe
  • Versicherung + Risiko

Jetzt Wissensvorsprung sichern!

Springer Professional "Wirtschaft"

Online-Abonnement

Mit Springer Professional "Wirtschaft" erhalten Sie Zugriff auf:

  • über 67.000 Bücher
  • über 340 Zeitschriften

aus folgenden Fachgebieten:

  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Finance + Banking
  • Management + Führung
  • Marketing + Vertrieb
  • Versicherung + Risiko




Jetzt Wissensvorsprung sichern!

Springer Professional "Technik"

Online-Abonnement

Mit Springer Professional "Technik" erhalten Sie Zugriff auf:

  • über 67.000 Bücher
  • über 390 Zeitschriften

aus folgenden Fachgebieten:

  • Automobil + Motoren
  • Bauwesen + Immobilien
  • Business IT + Informatik
  • Elektrotechnik + Elektronik
  • Energie + Nachhaltigkeit
  • Maschinenbau + Werkstoffe




 

Jetzt Wissensvorsprung sichern!

Appendix
Available only for authorised users
Footnotes
1
CR is based on resolution instead of superposition, because superposition’s ordering-based refinements would restrict unit-propagation and the selection of decision literals. In Sat-solvers unit-propagation is unrestricted (because it is very effective anyway) and the best literal selection strategies are not based on orderings. By extending unrestricted resolution, CR remains general enough to admit the strategies used by Sat-solvers.
 
2
By Herbrand’s theorem, a finite number of instances would suffice in the case of an unsatisfiable clause set. As the logic is undecidable, however, there is no way to know in advance how many “several” might be.
 
3
This rule is also known as unit-resulting resolution [24, 25]. Here we use the name unit-propagating resolution instead in order to make the connection with the technique of unit-propagation more explicit.
 
4
As mentioned in Sect. 3, modern Sat-solvers implement optimized clause learning procedures that may also contain duals of propagated literals. A modification of CR ’s \(\mathbf {cl}\) inference rule to cover more sophisticated clause learning procedures is briefly discussed in Sect. 4.2.
 
5
The usual definition of UIP in terms of conflict graphs also relies on the notion of decision level of assigned literals and requires that the propagated literal be assigned at the current decision level. Therefore, our definition is slightly more general. This is intentional. The notion of decision level, which keeps track of the order in which decision literals were assigned, is beyond the purely proof-theoretical scope of this paper, as it relates to particular proof search and backtracking procedures.
 
6
CND is a calculus for classical logic: the law of excluded middle can be easily derived with a single application of implication introduction. Interestingly, its classicality is implicit in the use of involutive negation and the equivalence involving disjunctions and implications.
 
7
Since we assume that distinct clauses in \(\psi '\) do not share variables and \(\psi '\) is tree-like, we do not need to worry about variable clashes in the composition of all substitutions. The topological order is needed because a variable x introduced by a substitution \(\sigma _1\) may be in the domain of another substitution \(\sigma _2\) occurring below \(\sigma _1\). In this case, the topologically ordered composition is \(\sigma _1 \sigma _2\) (i.e. apply first \(\sigma _1\) and then \(\sigma _2\)).
 
8
TPTP’s general proof format [30] requires that the conclusion of an inference rule be a logical consequence of (or equi-satisfiable to) its premises. This limitation prevents an easy representation of natural deduction’s implication introduction rule, tableaux’s \(\beta \) rule or splitting. CR ’s conflict-driven clause learning is also affected by this limitation.
 
9
It is assumed (without loss of generality) that, for every i, \(\varGamma _i\) is actually used in \(\varphi _i\). Otherwise, if \(\varGamma _j\) were not used in \(\varphi _j\) for some j, \(\varphi _j\) would already be a refutation of S, and it would not be necessary to split \(\varGamma _1 \vee \ldots \vee \varGamma _k\).
 
10
It may be reused many times, since \(\varphi _i\) does not need to be tree-like.
 
11
Although antecedents of sequents and a Sat-solver’s trail resemble each other, as both store decision literals, they are not quite the same thing. Whereas a Sat-solver’s trail is typically a global structure, each sequent’s antecedent is local and stores only the decisions that have been necessary to derive the sequent’s succedent.
 
Literature
1.
go back to reference Alagi, G., Weidenbach, C.: Non-redundant clause learning. In: FroCoS, pp. 69–84 (2015) Alagi, G., Weidenbach, C.: Non-redundant clause learning. In: FroCoS, pp. 69–84 (2015)
2.
go back to reference Beth, E.W.: Semantic entailment and formal derivability. In: Mededelingen van de Koninklijke Nederlandse Akademie van Wetenschappen, Afdeling Letterkunde 18(13), 309–342 (1955) Beth, E.W.: Semantic entailment and formal derivability. In: Mededelingen van de Koninklijke Nederlandse Akademie van Wetenschappen, Afdeling Letterkunde 18(13), 309–342 (1955)
3.
go back to reference Bachmair, L., Ganzinger, H.: Completion of first-order clauses with equality by strict superposition (Extended Abstract). In: 2nd International Workshop Conditional and Typed Rewriting Systems, LNCS 516, pp. 162–180. Springer, Berlin (1990) Bachmair, L., Ganzinger, H.: Completion of first-order clauses with equality by strict superposition (Extended Abstract). In: 2nd International Workshop Conditional and Typed Rewriting Systems, LNCS 516, pp. 162–180. Springer, Berlin (1990)
4.
go back to reference Bachmair, L., Ganzinger, H.: Rewrite-based equational theorem proving with selection and simplification. J. Log. Comput. 4(3), 217–247 (1994)MathSciNetCrossRefMATH Bachmair, L., Ganzinger, H.: Rewrite-based equational theorem proving with selection and simplification. J. Log. Comput. 4(3), 217–247 (1994)MathSciNetCrossRefMATH
5.
go back to reference Baumgartner, P.: A first order Davis-Putnam-Longeman-Loveland procedure. In: Proceedings of the 17th International Conference on Automated Deduction (CADE), pp. 200–219 (2000) Baumgartner, P.: A first order Davis-Putnam-Longeman-Loveland procedure. In: Proceedings of the 17th International Conference on Automated Deduction (CADE), pp. 200–219 (2000)
6.
go back to reference Baumgartner, P.: Model evolution based theorem proving. IEEE Intel. Syst. 29(1), 4–10 (2014)CrossRef Baumgartner, P.: Model evolution based theorem proving. IEEE Intel. Syst. 29(1), 4–10 (2014)CrossRef
7.
go back to reference Baumgartner, P., Tinelli, C.: The model evolution calculus. In: CADE, pp. 350–364 (2003) Baumgartner, P., Tinelli, C.: The model evolution calculus. In: CADE, pp. 350–364 (2003)
8.
go back to reference Baumgartner, P., Fuchs, A., Tinelli, C.: Lemma learning in the model evolution calculus. In: LPAR, pp. 572–586 (2006) Baumgartner, P., Fuchs, A., Tinelli, C.: Lemma learning in the model evolution calculus. In: LPAR, pp. 572–586 (2006)
9.
go back to reference Biere, A.: PicoSAT Essentials. JSAT 4(2–4), 75–97 (2008) Biere, A.: PicoSAT Essentials. JSAT 4(2–4), 75–97 (2008)
10.
go back to reference Bonacina, M.P.: Plaisted, DA.: SGGS theorem proving: an exposition. In: Schulz, S., de Moura, L., Konev, B. (eds.) 4th Workshop on Practical Aspects of Automated Reasoning, PAAR@IJCAR 2014, Vienna, Austria, 2014, vol. 31, pp. 25–38. EasyChair (2014) Bonacina, M.P.: Plaisted, DA.: SGGS theorem proving: an exposition. In: Schulz, S., de Moura, L., Konev, B. (eds.) 4th Workshop on Practical Aspects of Automated Reasoning, PAAR@IJCAR 2014, Vienna, Austria, 2014, vol. 31, pp. 25–38. EasyChair (2014)
11.
go back to reference Bonacina, M.P., Plaisted, D.A.: Semantically-guided goal-sensitive reasoning: model representation. J. Autom. Reason. 56(2), 113–141 (2016) Bonacina, M.P., Plaisted, D.A.: Semantically-guided goal-sensitive reasoning: model representation. J. Autom. Reason. 56(2), 113–141 (2016)
12.
go back to reference Brown, CE.: Satallax: An automatic higher-order prover. In: IJCAR, pp. 111–117 (2012) Brown, CE.: Satallax: An automatic higher-order prover. In: IJCAR, pp. 111–117 (2012)
13.
go back to reference Brown, CE.: Reducing higher-order theorem proving to a sequence of SAT problems. J. Autom. Reason. 51(1), 57–77 (2013) Brown, CE.: Reducing higher-order theorem proving to a sequence of SAT problems. J. Autom. Reason. 51(1), 57–77 (2013)
14.
go back to reference Claessen, K.: The anatomy of equinox—an extensible automated reasoning tool for first-order logic and beyond (Talk Abstract). In: Proceedings of the 23rd International Conference on Automated Deduction (CADE-23), pp. 1–3 (2011) Claessen, K.: The anatomy of equinox—an extensible automated reasoning tool for first-order logic and beyond (Talk Abstract). In: Proceedings of the 23rd International Conference on Automated Deduction (CADE-23), pp. 1–3 (2011)
17.
go back to reference de Nivelle, H., Meng, J.: Geometric resolution: a proof procedure based on finite model search. In: 3rd International Joint Conference on Automated Reasoning (IJCAR), pp. 303–317 (2006) de Nivelle, H., Meng, J.: Geometric resolution: a proof procedure based on finite model search. In: 3rd International Joint Conference on Automated Reasoning (IJCAR), pp. 303–317 (2006)
18.
go back to reference Gentzen, G.: Untersuchungen über das logische Schließen I & II. Math. Z. 39(1), 176–210, 405–431 (1935) Gentzen, G.: Untersuchungen über das logische Schließen I & II. Math. Z. 39(1), 176–210, 405–431 (1935)
19.
go back to reference Barbosa, H., Fontaine, P.: Congruence closure with free variables (Work in Progress). In: 2nd International Workshop on Quantification (2015) Barbosa, H., Fontaine, P.: Congruence closure with free variables (Work in Progress). In: 2nd International Workshop on Quantification (2015)
20.
go back to reference Korovin, K.: iProver—an instantiation-based theorem prover for first-order logic (system description)”. In: International Joint Conference on Automated Reasoning (IJCAR), pp. 292–298 (2008) Korovin, K.: iProver—an instantiation-based theorem prover for first-order logic (system description)”. In: International Joint Conference on Automated Reasoning (IJCAR), pp. 292–298 (2008)
21.
go back to reference Korovin, K.: Inst-gen—a modular approach to instantiation-based automated reasoning. In: Voronkov, A., Weidenbach, C. (eds.) Programming Logics, vol. 7797, pp. 239–270. Springer, Berlin (2013) Korovin, K.: Inst-gen—a modular approach to instantiation-based automated reasoning. In: Voronkov, A., Weidenbach, C. (eds.) Programming Logics, vol. 7797, pp. 239–270. Springer, Berlin (2013)
22.
go back to reference Marques-Silva, J., Sakallah, K.A.: GRASP—a new search algorithm for satisfiability. In: International Conference on Computer-Aided Design, pp. 220–227 (1996) Marques-Silva, J., Sakallah, K.A.: GRASP—a new search algorithm for satisfiability. In: International Conference on Computer-Aided Design, pp. 220–227 (1996)
23.
go back to reference Marques-Silva, J., Lynce, I., Malik, S.: Conflict-driven clause learning SAT solvers. In: Handbook of Satisfiability, pp. 127–149 (2008) Marques-Silva, J., Lynce, I., Malik, S.: Conflict-driven clause learning SAT solvers. In: Handbook of Satisfiability, pp. 127–149 (2008)
24.
go back to reference McCharen, J., Overbeek, R., Wos, L.: Complexity and related enhancements for automated theorem-proving programs. Comput. Math. Appl. 2, 1–16 (1976)MATH McCharen, J., Overbeek, R., Wos, L.: Complexity and related enhancements for automated theorem-proving programs. Comput. Math. Appl. 2, 1–16 (1976)MATH
26.
go back to reference Riazanov, A., Voronkov, A.: The design and implementation of VAMPIRE. AI Commun. 15(2–3), 91–110 (2002)MATH Riazanov, A., Voronkov, A.: The design and implementation of VAMPIRE. AI Commun. 15(2–3), 91–110 (2002)MATH
28.
go back to reference Robinson, G., Wos, L.: Paramodulation and theorem-proving in first-order thories with equality. Mach. Intell. 4, 135–150 (1969)MATH Robinson, G., Wos, L.: Paramodulation and theorem-proving in first-order thories with equality. Mach. Intell. 4, 135–150 (1969)MATH
29.
go back to reference Schultz, S.: System description: E 1.8. In: LPAR, pp. 735–743 (2013) Schultz, S.: System description: E 1.8. In: LPAR, pp. 735–743 (2013)
30.
go back to reference Sutcliffe, G.: The TPTP problem library and associated infrastructure: the FOF and CNF parts, v3.5.0. J. Autom. Reason. 43(4), 337–362 (2009)MathSciNetCrossRefMATH Sutcliffe, G.: The TPTP problem library and associated infrastructure: the FOF and CNF parts, v3.5.0. J. Autom. Reason. 43(4), 337–362 (2009)MathSciNetCrossRefMATH
31.
go back to reference Voronkov, A.: AVATAR: The architecture for first-order theorem provers. In: CAV, pp. 696–710 (2014) Voronkov, A.: AVATAR: The architecture for first-order theorem provers. In: CAV, pp. 696–710 (2014)
32.
go back to reference Waldmann, U.: Superposition. In: Paleo, B.W. (eds.) Towards an Encyclopaedia of Proof Systems, p. 29. College Publications, London, UK (2017) Waldmann, U.: Superposition. In: Paleo, B.W. (eds.) Towards an Encyclopaedia of Proof Systems, p. 29. College Publications, London, UK (2017)
33.
go back to reference Waldmann, U.: Saturation with redundancy. In: Paleo, B.W. (eds.) Towards an Encyclopaedia of Proof Systems, p. 30. College Publications, London, UK (2017) Waldmann, U.: Saturation with redundancy. In: Paleo, B.W. (eds.) Towards an Encyclopaedia of Proof Systems, p. 30. College Publications, London, UK (2017)
34.
go back to reference Weidenbach, C.: Combining superposition, sorts and splitting. In: Robinson, J.A., Voronkov, A. (eds.) Handbook of Automated Reasoning, pp. 1965–2013. Elsevier and MIT Press (2001) Weidenbach, C.: Combining superposition, sorts and splitting. In: Robinson, J.A., Voronkov, A. (eds.) Handbook of Automated Reasoning, pp. 1965–2013. Elsevier and MIT Press (2001)
35.
go back to reference Weidenbach, C.: The Theory of SPASS version 2.0. In: SPASS 2.0 documentation Weidenbach, C.: The Theory of SPASS version 2.0. In: SPASS 2.0 documentation
36.
go back to reference Weidenbach, C., Dimova, D., Fietzke, A., Kumar, R., Suda, M., Wischnewski, P.: SPASS Version 3.5. In: CADE, pp. 140–145 (2009) Weidenbach, C., Dimova, D., Fietzke, A., Kumar, R., Suda, M., Wischnewski, P.: SPASS Version 3.5. In: CADE, pp. 140–145 (2009)
37.
go back to reference Wetzler, N., Heule, M., Hunt Jr, WA.: DRAT-trim: Efficient checking and trimming using expressive clausal proofs. In: SAT, pp. 422–429 (2014) Wetzler, N., Heule, M., Hunt Jr, WA.: DRAT-trim: Efficient checking and trimming using expressive clausal proofs. In: SAT, pp. 422–429 (2014)
38.
go back to reference Zhang, L., Madigan, CF., Moskewicz, MH., Malik, S.: Efficient conflict driven learning in a Boolean satisfiability solver. In: International Conference on Computer-Aided Design, pp. 279–285 (2001) Zhang, L., Madigan, CF., Moskewicz, MH., Malik, S.: Efficient conflict driven learning in a Boolean satisfiability solver. In: International Conference on Computer-Aided Design, pp. 279–285 (2001)
Metadata
Title
Conflict Resolution: A First-Order Resolution Calculus with Decision Literals and Conflict-Driven Clause Learning
Authors
John Slaney
Bruno Woltzenlogel Paleo
Publication date
24-02-2017
Publisher
Springer Netherlands
Published in
Journal of Automated Reasoning / Issue 2/2018
Print ISSN: 0168-7433
Electronic ISSN: 1573-0670
DOI
https://doi.org/10.1007/s10817-017-9408-6

Other articles of this Issue 2/2018

Journal of Automated Reasoning 2/2018 Go to the issue

Premium Partner