Implementing Integrity Constraints in an Existing Belief Revision System

SNePS is a mature knowledge representation, reasoning, and acting system that has long contained a belief revision subsystem, called SNeBR. SNeBR is triggered when an explicit contradiction is introduced into the SNePS belief space, either because of a user's new assertion, or because of a user's query. SNeBR then makes the user decide what belief to remove from the belief space in order to restore consistency, although it provides information to help the user in making that decision. We have recently added automatic belief revision to SNeBR, by which, under certain circumstances, SNeBR decides by itself which belief to remove, and then informs the user of the decision and its consequences. We have used the well-known belief revision integrity constraints as a guide in designing automatic belief revision, taking into account, however, that SNePS's belief space is not deductively closed, and that it would be infeasible to form the deductive closure in order to decide what belief to remove. This paper briefly describes SNeBR both before and after this revision, discusses how we adapted the integrity constraints for this purpose, and gives an example of the new SNeBR in action.

[1]  Recovering a Consistent Theory from an Inconsistent Belief Set: Theory Extraction , 1998 .

[2]  Stuart C. Shapiro,et al.  Intensional Concepts in Propositional Semantic Networks , 1982, Cogn. Sci..

[3]  Stuart C. Shapiro,et al.  Reasoning in Multiple Belief Spaces , 1983, IJCAI.

[4]  Frances L. Johnson,et al.  Formalizing a Deductively Open Belief Space , 2000 .

[5]  Stuart C. Shapiro,et al.  A Model for Belief Revision , 1988, Artif. Intell..

[6]  João P. Martins,et al.  SNePSwD: A newcomer to the SNePS family , 1993, J. Exp. Theor. Artif. Intell..

[7]  F. Lehmann,et al.  Semantic Networks in Artificial Intelligence , 1992 .

[8]  Mark Okrent.  The truth, the whole truth, and nothing but the truth , 1993 .

[9]  Stuart C. Shapiro,et al.  Automatic Belief Revision in SNePS , 2000, ArXiv.

[10]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[11]  João P. Martins,et al.  The Truth, the Whole Truth, and Nothing But the Truth , 1990, AI Mag..

[12]  SVEN OVE HANSSON,et al.  Reversing the Levi identity , 1993, J. Philos. Log..

[13]  Karen Ehrlich.  Automatic vocabulary expansion through narrative context , 1995 .

[14]  Peter Gärdenfors,et al.  Belief Revision , 1995 .

[15]  David Makinson,et al.  On the logic of theory change: Safe contraction , 1985, Stud Logica.

[16]  Stuart C. Shapiro,et al.  Belief spaces as sets of propositions , 1993, J. Exp. Theor. Artif. Intell..

[17]  Peter Gärdenfors,et al.  On the logic of theory change: Partial meet contraction and revision functions , 1985, Journal of Symbolic Logic.

[18]  William J. Rapaport,et al.  A computational theory of vocabulary acquisition , 2000 .

[19]  Sven Ove Hansson,et al.  Theory contraction and base contraction unified , 1993, Journal of Symbolic Logic.

[20]  W. Rapaport,et al.  The SNePS family , 1992 .

[21]  Stuart C. Shapiro,et al.  Book Reviews: Natural Language Processing and Knowledge Representation: Language for Knowledge and Knowledge for Language , 2001, CL.

[22]  Johan de Kleer,et al.  Choices Without Backtracking , 1984, AAAI.

[23]  Bernhard Nebel,et al.  A Knowledge Level Analysis of Belief Revision , 1989, KR.