Abstract
Approximation fixpoint theory (AFT) provides an algebraic framework for the study of fixpoints of operators on bilattices and has found its applications in characterizing semantics for various types of logic programs and nonmonotonic languages. In this paper, we show one more application of this kind: the alternating fixpoint operator by Knorr et al. [8] for the study of well-founded semantics for hybrid MKNF knowledge bases is in fact an approximator of AFT in disguise, which, thanks to the power of abstraction of AFT, characterizes not only the well-founded semantics but also two-valued as well as three-valued semantics for hybrid MKNF knowledge bases. Furthermore, we show an improved approximator for these knowledge bases, of which the least stable fixpoint is information richer than the one formulated from Knorr et al.’s construction. This leads to an improved computation for the well-founded semantics.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
Notes
- 1.
We can in addition require that an approximator A be consistent for at least one exact pair. This will eliminate the undesired situation that if a \(\le _p\)-monotone operator A is inconsistent on each exact pair, then it approximates every operator O, trivially.
- 2.
In [6], A-contracting pairs were called A-reliable.
References
Antić, C., Eiter, T., Fink, M.: Hex semantics via approximation fixpoint theory. In: Cabalar, P., Son, T.C. (eds.) LPNMR 2013. LNCS (LNAI), vol. 8148, pp. 102–115. Springer, Heidelberg (2013). https://doi.org/10.1007/978-3-642-40564-8_11
Bi, Y., You, J.-H., Feng, Z.: A generalization of approximation fixpoint theory and application. In: Kontchakov, R., Mugnier, M.-L. (eds.) RR 2014. LNCS, vol. 8741, pp. 45–59. Springer, Cham (2014). https://doi.org/10.1007/978-3-319-11113-1_4
Bogaerts, B., Cruz-Filipe, L.: Fixpoint semantics for active integrity constraints. Artif. Intell. 255, 43–70 (2018)
De Bona, G., Hunter, A.: Localising iceberg inconsistencies. Artif. Intell. 246, 118–151 (2017)
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, Boston (2000). https://doi.org/10.1007/978-1-4615-1567-8_6
Denecker, M., Marek, V.W., Truszczynski, M.: Ultimate approximation and its application in nonmonotonic knowledge representation systems. Inf. Comput. 192(1), 84–121 (2004)
Denecker, M., Vennekens, J.: Well-founded semantics and the algebraic theory of non-monotone inductive definitions. In: Baral, C., Brewka, G., Schlipf, J. (eds.) LPNMR 2007. LNCS (LNAI), vol. 4483, pp. 84–96. Springer, Heidelberg (2007). https://doi.org/10.1007/978-3-540-72200-7_9
Knorr, M., Alferes, J.J., Hitzler, P.: Local closed world reasoning with description logics under the well-founded semantics. Artif. Intell. 175(9–10), 1528–1554 (2011)
Lifschitz, V.: Nonmonotonic databases and epistemic queries. In: Proceedings of the 12th International Joint Conference on Artificial Intelligence, IJCAI 1991, pp. 381–386, Sydney, Australia (1991)
Liu, F., You, J.-H.: Three-valued semantics for hybrid MKNF knowledge bases revisited. Artif. Intell. 252, 123–138 (2017)
Motik, B., Rosati, R.: A faithful integration of description logics with logic programming. In: Proceedings of the 19th International Joint Conference on Artificial Intelligence, IJCAI 2007, Hyderabad, India, pp. 477–482 (2007)
Motik, B., Rosati, R.: Reconciling description logics and rules. J. ACM 57(5), 1–62 (2010)
Pelov, N., Denecker, M., Bruynooghe, M.: Well-founded and stable semantics of logic programs with aggregates. Theory Pract. Logic Program. 7(3), 301–353 (2007)
Strass, H.: Approximating operators and semantics for abstract dialectical frameworks. Artif. Intell. 205, 39–70 (2013)
Tarski, A.: A lattice-theoretical fixpoint theorem and its applications. Pac. J. Math. 5(2), 285–309 (1955)
van Emden, M.H., Kowalski, R.A.: The semantics of predicate logic as a programming language. J. ACM 23(4), 733–742 (1976)
Vennekens, J., Gilis, D., Denecker, M.: Splitting an operator: algebraic modularity results for logics with fixpoint semantics. ACM Trans. Comput. Logic 7(4), 765–797 (2006)
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2019 Springer Nature Switzerland AG
About this paper
Cite this paper
Liu, F., You, JH. (2019). Alternating Fixpoint Operator for Hybrid MKNF Knowledge Bases as an Approximator of AFT. In: Fodor, P., Montali, M., Calvanese, D., Roman, D. (eds) Rules and Reasoning. RuleML+RR 2019. Lecture Notes in Computer Science(), vol 11784. Springer, Cham. https://doi.org/10.1007/978-3-030-31095-0_8
Download citation
DOI: https://doi.org/10.1007/978-3-030-31095-0_8
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-31094-3
Online ISBN: 978-3-030-31095-0
eBook Packages: Computer ScienceComputer Science (R0)