Abstract
We develop an abstract theory of justifications suitable for describing the semantics of a range of logics in knowledge representation, computational and mathematical logic. A theory or program in one of these logics induces a semantical structure called a justification frame. Such a justification frame defines a class of justifications each of which embodies a potential reason why its facts are true. By defining various evaluation functions for these justifications, a range of different semantics are obtained. By allowing nesting of justification frames, various language constructs can be integrated in a seamless way. The theory provides elegant and compact formalisations of existing and new semantics in logics of various areas, showing unexpected commonalities and interrelations, and creating opportunities for new expressive knowledge representation formalisms.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Similar content being viewed by others
Notes
- 1.
Negation in the head of (extended) answer set programs is different from the negation studied here, and the justification semantics defined below is not directly suitable to compute answer sets of programs with explicit negation. We focus on systems where the rules for facts and their negations are complementary, hence negation is classical. In contrast, rules of ASP for negative literals are independent of those for positive literals.
- 2.
By dropping the constraint that \({\mathcal {F}_o}\) consists of logical facts only, we obtain extensions of all main semantics for a parameterized variant of logic programming.
- 3.
This should not be confused with the nested logic programs of [22], where nesting refers to the expressions inside a logic program rule, and not sets of rules being nested altogether.
References
Pelov, N., Denecker, M., Bruynooghe, M.: Well-founded and stable semantics of logic programs with aggregates. TPLP 7(3), 301–353 (2007)
Son, T.C., Pontelli, E.: A constructive semantic characterization of aggregates in answer set programming. TPLP 7(3), 355–375 (2007)
Denecker, M., De Schreye, D.: Justification semantics: A unifying framework for the semantics of logic programs. In: LPNMR, pp. 365–379. MIT Press (1993)
Denecker, M., Marek, V., Truszczyński, M.: Approximations, stable operators, well-founded fixpoints and applications in nonmonotonic reasoning. In: Minker, J. (ed.) Logic-Based Artificial Intelligence, pp. 127–144. Springer, New York (2000)
Denecker, M., Marek, V., Truszczyński, M.: Ultimate approximation and its application in nonmonotonic knowledge representation systems. Inf. Comput. 192(1), 84–121 (2004)
Kozen, D.: Results on the propositional \(\mu \)-calculus. Theoret. Comput. Sci. 27(1), 333–354 (1983)
Park, D.: Fixpoint induction and proofs of program properties. Mach. Intell. 5, 59–78 (1969)
Gebser, M., Kaufmann, B., Schaub, T.: Conflict-driven answer set solving: from theory to practice. Artif. Intell. 187, 52–89 (2012)
Mariën, M., Wittocx, J., Denecker, M., Bruynooghe, M.: SAT(ID): satisfiability of propositional logic extended with inductive definitions. In: Kleine Büning, H., Zhao, X. (eds.) SAT 2008. LNCS, vol. 4996, pp. 211–224. Springer, Heidelberg (2008)
Gelfond, M., Lifschitz, V.: Classical negation in logic programs and disjunctive databases. New Gener. Comput. 9, 365–385 (1991)
Dung, P.M.: On the acceptability of arguments and its fundamental role in nonmonotonic reasoning, logic programming and n-person games. Artif. Intell. 77, 321–358 (1995)
Gupta, G., Bansal, A., Min, R., Simon, L., Mallya, A.: Coinductive logic programming and its applications. In: Dahl, V., Niemelä, I. (eds.) ICLP 2007. LNCS, vol. 4670, pp. 27–44. Springer, Heidelberg (2007)
Hou, P., De Cat, B., Denecker, M.: FO(FD): extending classical logic with rule-based fixpoint definitions. Theor. Pract. Log. Program. 10(4–6), 581–596 (2010)
van Emden, M.H., Kowalski, R.A.: The semantics of predicate logic as a programming language. J. ACM 23(4), 733–742 (1976)
Fitting, M.: Fixpoint semantics for logic programming: a survey. Theoret. Comput. Sci. 278(1–2), 25–51 (2002)
Strass, H.: Approximating operators and semantics for abstract dialectical frameworks. Artif. Intell. 205, 39–70 (2013)
Fages, F.: A new fixpoint semantis for general logic programs compared with the well-founded and the stable model semantics. In: ICLP, p. 443. MIT Press (1990)
Schulz, C., Toni, F.: ABA-based answer set justification. Theor. Pract. Log. Program. 13(4-5-Online-Supplement) (2013)
Cabalar, P., Fandinno, J., Fink, M.: Causal graph justifications of logic programs. Theor. Pract. Log. Program. 14(4–5), 603–618 (2014)
Pontelli, E., Son, T.C., Elkhatib, O.: Justifications for logic programs under answer set semantics. Theor. Pract. Log. Program. 9(1), 1–56 (2009)
Viegas Damásio, C., Analyti, A., Antoniou, G.: Justifications for logic programming. In: Cabalar, P., Son, T.C. (eds.) LPNMR 2013. LNCS, vol. 8148, pp. 530–542. Springer, Heidelberg (2013)
Lifschitz, V., Tang, L.R., Turner, H.: Nested expressions in logic programs. Ann. Math. Artif. Intell. 25(3–4), 369–389 (1999)
Hallnäs, L.: Partial inductive definitions. Theor. Comp. Sci. 87(1), 115–142 (1991)
Bondarenko, A., Dung, P.M., Kowalski, R.A., Toni, F.: An abstract, argumentation-theoretic approach to default reasoning. Artif. Intell. 93, 63–101 (1997)
Brewka, G., Woltran, S.: Abstract dialectical frameworks. In: KR, pp. 102–111 (2010)
Bogaerts, B., Vennekens, J., Denecker, M., Van den Bussche, J.: FO(C): a knowledge representation language of causality. TPLP 14((4–5–Online–Supplement)), 60–69 (2014)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2015 Springer International Publishing Switzerland
About this paper
Cite this paper
Denecker, M., Brewka, G., Strass, H. (2015). A Formal Theory of Justifications. In: Calimeri, F., Ianni, G., Truszczynski, M. (eds) Logic Programming and Nonmonotonic Reasoning. LPNMR 2015. Lecture Notes in Computer Science(), vol 9345. Springer, Cham. https://doi.org/10.1007/978-3-319-23264-5_22
Download citation
DOI: https://doi.org/10.1007/978-3-319-23264-5_22
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-319-23263-8
Online ISBN: 978-3-319-23264-5
eBook Packages: Computer ScienceComputer Science (R0)