Abstract
We discuss the general problem of revising a contradictory non-monotonic theory and we show that sometimes expanding the theory is more appropriate than contracting it in order to remove the contradiction. We apply this idea of theory-expansion to logic programs with negation and constraints.
Using the well-founded (wf-) model semantics for logic programs as our starting point we show that this model may be contradictory due to a clash between the assumption made in the wf-model to consider unfounded atoms to be false and the repercussions constraints can have on this assumption.
Then we show that the contradiction can be removed by adding rules to unfounded atoms in the program. We propose to use the noncontradictory wf-model of such an expansion as the semantics of the original program.
We develop a formal framework for program expansion, studying properties as completeness, minimality and computational complexity of expansions.
We think that program expansion is the best framework to study procedurally defined revision processes as proposed in truth maintenance and logic programming such as dependency-directed backtracking and the recently proposed contradiction removal semantics.
Using the framework of program expansions we are able to determine the complexity profiles of these approaches as well as significant generalizations of both of them.
This is a preview of subscription content, log in via an institution.
Preview
Unable to display preview. Download preview PDF.
References
C. Alchourrón, P. Gärdenfors and D. Makinson, On the Logic of Theory Change: Partial Meet Contraction and Revision Functions, Journal of Symbolic Logic, 50, 510–530, 1985.
J. Dix, Classifying Semantics of Logic Programs. In: A. Nerode et al. (eds), Proceedings LPNMR'91, MIT Press, 1991, pp. 166–180.
J. Doyle, A Truth Maintenance System, Artificial Intelligence 12, 1979.
P. Gärdenfors, Knowledge in Flux, MIT Press, Cambridge, MA, 1988.
M. R. Garey, D. S. Johnson, Computers and Intractability, Freeman, New York, 1979.
G. Gottlob, C. G. Fermüller, Removing redundancy from a clause, Artificial Intelligence, 61, (1993) 263–289
C. M. Jonker, Cautious Backtracking and Well-Founded Semantics in Truth Maintenance. Technical Report RUU-CS-91-26, Dept. of Computer Science, Utrecht University, 1991.
C. M. Jonker, Analysis of Dependency-Directed Backtracking: leading to Informative Backtracking. Technical Report to appear, Dept. of Philosophy and Dept. of Computer Science, Utrecht University, 1993.
Morris, P., Stable Closures, Defeasible Logic and Contradiction Tolerant Reasoning, Proceedings of the 7th National Conference on Artificial Intelligence, 1988.
L. M. Pereira, J. J. Alferes and J. N. Aparicio, Contradiction Removal within well-founded semantics. In: A. Nerode, W. Marek and V. S. Subrahmanian, (eds.), First International Workshop on Logic Programming and Non-monotonic Reasoning, MIT Press, 1991.
L. M. Pereira, J. J. Alferes and J. N. Aparicio, The Extended Stable Models of Contradiction Removal Semantics. In: P. Barahona, L. M. Pereira and A. Porto, (eds.), Proceedings — EPIA 91, Springer Verlag, Heidelberg, 1991.
L. M. Pereira, Personal Communication, Berlin 1992.
Pétrie, C.J., Revised Dependency-Directed Backtracking for Default Reasoning, Proc. AAAI, 1987.
H. Przymusinska and T. Przymusinski, Semantic Issues in Deductive Databases and Logic Programs, in: R. B. Banerji (ed), Formal Techniques in Artificial Intelligence, A Sourcebook, Elsevier, Amsterdam, 1990, pp. 321–367.
T. Przymusinski, Well-founded semantics coincides with three-valued stable semantics, Fundamenta Informaticae, XIII:445–463, 1990.
T. Przymusinski, Three-valued nonmonotonic formalisms and semantics of logic programs, Artificial Intelligence, 49, (1991), 309–343.
Reinfrank, M., Fundamentals and Logical Foundations of Truth Maintenance, Linköping Studies in Science and Technology. Dissertations no. 221, Linköping University, 1989.
A. Van Gelder, K. A. Ross and J. S. Schlipf, The well-founded semantics for general logic programs. Journal of the ACM, 38(3), pp. 620–650, 1991.
K. W. Wagner, Bounded Query Classes, Siam Journal On Computing, 19,5, pp. 833–846, 1990.
C. Witteveen, Expansions of Logic Programs, in: D. Pearce and G. Wagner (eds), Logics in Al, Springer Verlag, Berlin, 1992.
C. Witteveen and C. M. Jonker, Revision by expansion in logic programs, Reports of the Faculty of Technical Mathematics and Informatics no. 93-02, Delft University of Technology, 1993.
C. Witteveen and G. Brewka, Skeptical Reason Maintenance and Belief Revision, Artificial Intelligence, 61 (1993) 1–36.
Author information
Authors and Affiliations
Editor information
Rights and permissions
Copyright information
© 1994 Springer-Verlag Berlin Heidelberg
About this chapter
Cite this chapter
Witteveen, C., Jonker, C. (1994). Revision by expansion in logic programs. In: Lakemeyer, G., Nebel, B. (eds) Foundations of Knowledge Representation and Reasoning. Lecture Notes in Computer Science, vol 810. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-58107-3_19
Download citation
DOI: https://doi.org/10.1007/3-540-58107-3_19
Published:
Publisher Name: Springer, Berlin, Heidelberg
Print ISBN: 978-3-540-58107-9
Online ISBN: 978-3-540-48453-0
eBook Packages: Springer Book Archive