Abstract
This paper studies defeasible logic for representing legal theories. In defeasible logic, a literal can be ambiguous since a theory can support both the literal and its contrary. There have been several policies in handling ambiguities but choosing a policy is under judges’ discretion, which is unpredictable and possibly contradicts the legislators’ intentions. To prevent such a problem, this paper studies contrary prioritization, which restricts a defeasible theory to prioritize all pairs of rules in which heads are contrary to each other. This paper analyzes the complexity of contrary prioritization and the generality of contrary prioritized defeasible theories in the translations between such defeasible theories and stratified logic programs. This paper presents that contrary prioritization requires an effort of finding a correct assignment of the priorities between contrary pairs, and the effort makes the problem of contrary prioritization NP-complete. Furthermore, every contrary prioritized defeasible theory can be translated to a stratified logic program and vice versa. Hence, a contrary prioritized defeasible theory is as general as a stratified logic program.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Similar content being viewed by others
Notes
- 1.
Generally, > in defeasible logic is not required to be transitive. However, in this paper, we assume the transitivity to ensure that a closure of the priority is acyclic.
- 2.
This is a simplified representation for ease of exposition. A proper representation requires considering deontic modalities and strengths of permission cf. [13].
References
Antoniou, G.: Relating defeasible logic to extended logic programs. In: Vlahavas, I.P., Spyropoulos, C.D. (eds.) SETN 2002. LNCS (LNAI), vol. 2308, pp. 54–64. Springer, Heidelberg (2002). https://doi.org/10.1007/3-540-46014-4_6
Antoniou, G., Billington, D., Governatori, G., Maher, M.J.: Embedding defeasible logic into logic programming. Theory Pract. Logic Program. 6(6), 703–735 (2006)
Antoniou, G., Maher, M.J., Billington, D.: Defeasible logic versus logic programming without negation as failure. J. Log. Program. 42(1), 47–57 (2000)
Apt, K.R., Blair, H.A., Walker, A.: Towards a theory of declarative knowledge. In: Foundations of Deductive Databases and Logic Programming, pp. 89–148. Morgan Kaufmann, Burlington (1988)
Araszkiewicz, M., Płeszka, K.: The concept of normative consequence and legislative discourse. In: Araszkiewicz, M., Płeszka, K. (eds.) Logic in the Theory and Practice of Lawmaking. Legisprudence Library, pp. 253–297. Springer, Cham (2015). https://doi.org/10.1007/978-3-319-19575-9_10
Billington, D., Antoniou, G., Governatori, G., Maher, M.: An inclusion theorem for defeasible logics. ACM Trans. Comput. Log. (TOCL) 12(1), 1–27 (2010)
Brewka, G.: On the relationship between defeasible logic and well-founded semantics. In: Eiter, T., Faber, W., Truszczyński, M. (eds.) LPNMR 2001. LNCS (LNAI), vol. 2173, pp. 121–132. Springer, Heidelberg (2001). https://doi.org/10.1007/3-540-45402-0_9
Fungwacharakorn, W., Tsushima, K., Satoh, K.: On semantics-based minimal revision for legal reasoning. In: Proceedings of the 18th International Conference on Artificial Intelligence and Law - ICAIL 2021. ACM, New York (2021)
Gelfond, M., Lifschitz, V.: The stable model semantics for logic programming. In: Kowalski, R., Bowen, Kenneth (eds.) Proceedings of International Logic Programming Conference and Symposium, vol. 88, pp. 1070–1080. MIT Press, Cambridge (1988)
Governatori, G., Maher, M.J.: Annotated defeasible logic. Theory Pract. Logic Program. 17(5–6), 819–836 (2017)
Governatori, G., Maher, M.J., Antoniou, G., Billington, D.: Argumentation semantics for defeasible logic. J. Log. Comput. 14(5), 675–702 (2004)
Governatori, G., Olivieri, F., Cristani, M., Scannapieco, S.: Revision of defeasible preferences. Int. J. Approximate Reasoning 104, 205–230 (2019)
Governatori, G., Olivieri, F., Rotolo, A., Scannapieco, S.: Computing strong and weak permissions in defeasible logic. J. Philos. Log. 42(6), 799–829 (2013)
Governatori, G., Olivieri, F., Scannapieco, S., Cristani, M.: Superiority based revision of defeasible theories. In: Dean, M., Hall, J., Rotolo, A., Tabet, S. (eds.) RuleML 2010. LNCS, vol. 6403, pp. 104–118. Springer, Heidelberg (2010). https://doi.org/10.1007/978-3-642-16289-3_10
Governatori, G., Olivieri, F., Scannapieco, S., Cristani, M.: The hardness of revising defeasible preferences. In: Bikakis, A., Fodor, P., Roman, D. (eds.) RuleML 2014. LNCS, vol. 8620, pp. 168–177. Springer, Cham (2014). https://doi.org/10.1007/978-3-319-09870-8_12
Governatori, G., Sartor, G.: Burdens of proof in monological argumentation. In: Legal Knowledge and Information Systems, pp. 57–66. IOS Press (2010)
Ito, S.: Basis of Ultimate Facts. Yuhikaku (2001)
Kunen, K.: Signed data dependencies in logic programs. Technical report, University of Wisconsin-Madison Department of Computer Sciences (1987)
Maher, M.J.: Propositional defeasible logic has linear complexity. Theory Pract. Logic Program. 1(6), 691–711 (2001)
Maranhão, J.S.A.: Conservative coherentist closure of legal systems. In: Araszkiewicz, M., Płeszka, K. (eds.) Logic in the Theory and Practice of Lawmaking. LL, vol. 2, pp. 115–136. Springer, Cham (2015). https://doi.org/10.1007/978-3-319-19575-9_4
McCarty, L.T.: Some arguments about legal arguments. In: Proceedings of the 6th International Conference on Artificial Intelligence and Law, pp. 215–224 (1997)
Merigoux, D., Chataing, N., Protzenko, J.: Catala: a programming language for the law. In: International Conference on Functional Programming. Proceedings of the ACM on Programming Languages, pp. 1–29. ACM, Virtual, South Korea (2021)
Nute, D.: Defeasible logic. In: Bartenstein, O., Geske, U., Hannebauer, M., Yoshie, O. (eds.) INAP 2001. LNCS (LNAI), vol. 2543, pp. 151–169. Springer, Heidelberg (2003). https://doi.org/10.1007/3-540-36524-9_13
Prakken, H.: Logical Tools for Modelling Legal Argument: A Study of Defeasible Reasoning in Law. Kluwer Academic Publishers (1997)
Prakken, H., Sartor, G.: Formalising arguments about the burden of persuasion. In: Proceedings of the 11th International Conference on Artificial Intelligence and Law, pp. 97–106 (2007)
Prakken, H., Wyner, A., Bench-Capon, T., Atkinson, K.: A formalization of argumentation schemes for legal case-based reasoning in ASPIC+. J. Log. Comput. 25(5), 1141–1166 (2015)
Przymusinska, H., Przymusinski, T.: Semantic issues in deductive databases and logic programs. In: Formal Techniques in Artificial Intelligence. Citeseer (1990)
Rotolo, A., Roversi, C.: Constitutive rules and coherence in legal argumentation: the case of extensive and restrictive interpretation. In: Dahlman, C., Feteris, E. (eds.) Legal Argumentation Theory: Cross-Disciplinary Perspectives. Law and Philosophy Library, vol. 102, pp. 163–188. Springer, Dordrecht (2013). https://doi.org/10.1007/978-94-007-4670-1_11
Satoh, K., et al.: PROLEG: an implementation of the presupposed ultimate fact theory of Japanese civil code by PROLOG technology. In: Onada, T., Bekki, D., McCready, E. (eds.) JSAI-isAI 2010. LNCS (LNAI), vol. 6797, pp. 153–164. Springer, Heidelberg (2011). https://doi.org/10.1007/978-3-642-25655-4_14
Satoh, K., Kogawa, T., Okada, N., Omori, K., Omura, S., Tsuchiya, K.: On generality of PROLEG knowledge representation. In: Proceedings of the 6th International Workshop on Juris-Informatics (JURISIN 2012), Miyazaki, Japan, pp. 115–128 (2012)
Satoh, K., Kubota, M., Nishigai, Y., Takano, C.: Translating the Japanese presupposed ultimate fact theory into logic programming. In: Proceedings of the 2009 Conference on Legal Knowledge and Information Systems: JURIX 2009: The Twenty-Second Annual Conference, pp. 162–171. IOS Press, Amsterdam (2009)
Satoh, K., Tojo, S., Suzuki, Y.: Formalizing a switch of burden of proof by logic programming. In: Proceedings of the First International Workshop on Juris-Informatics (JURISIN 2007), pp. 76–85 (2007)
Sergot, M.J., Sadri, F., Kowalski, R.A., Kriwaczek, F., Hammond, P., Cory, H.T.: The British nationality act as a logic program. Commun. ACM 29(5), 370–386 (1986)
Sherman, D.M.: A prolog model of the income tax act of Canada. In: Proceedings of the 1st International Conference on Artificial Intelligence and Law, pp. 127–136. Association for Computing Machinery, New York (1987)
Stein, L.A.: Resolving ambiguity in nonmonotonic inheritance hierarchies. Artif. Intell. 55(2–3), 259–310 (1992)
Acknowledgements
The authors would like to thank all anonymous reviewers for insightful suggestions and comments. This work was supported by JSPS KAKENHI Grant Numbers, JP17H06103 and JP19H05470 and JST, AIP Trilateral AI Research, Grant Number JPMJCR20G4.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2023 The Author(s), under exclusive license to Springer Nature Switzerland AG
About this paper
Cite this paper
Fungwacharakorn, W., Tsushima, K., Satoh, K. (2023). On Complexity and Generality of Contrary Prioritized Defeasible Theory. In: Takama, Y., Yada, K., Satoh, K., Arai, S. (eds) New Frontiers in Artificial Intelligence. JSAI-isAI 2022. Lecture Notes in Computer Science(), vol 13859. Springer, Cham. https://doi.org/10.1007/978-3-031-29168-5_2
Download citation
DOI: https://doi.org/10.1007/978-3-031-29168-5_2
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-031-29167-8
Online ISBN: 978-3-031-29168-5
eBook Packages: Computer ScienceComputer Science (R0)