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Inferential equivalence, normal forms, and isomorphisms of knowledge bases in institutions of conditional logics

Published: 08 April 2019 Publication History

Abstract

Conditionals of the form "If A, then usually B" play an important role in formal approaches to knowledge representation and reasoning. Sets of such conditionals, called a knowledge base, may represent the explicitly given knowledge of an intelligent agent. For many operations involving kowledge bases, it is advantageous to have a compact and standardized form for them. In this paper, we show how to obtain a unique minimal normal form for every conditional knowledge base. The normal form is independent of a specific notion of semantic models and their particular notion of satisfaction between models and conditionals. This abstraction is achieved by employing Goguen and Burstall's framework of institutions and introducing the general notion of an institution of conditional logic. It covers previously proposed formalizations of conditional logics as institutions with specific semantics, like total preorders on worlds, possibility distributions, ranking functions, or big-stepped probabilities. The concepts of model equivalence and elementwise equivalence of knowledge bases are generalized first to arbitrary institutions of conditional logic and then further by taking also isomorphisms into account. We introduce the notion of inferential equivalence of knowledge bases for two different nonmonotonic inference relations induced by a knowledge base. For inferential equivalences with respect to these nonmonotonic inference relations, we prove how they are preserved under normalization and isomorphisms.

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Cited By

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  • (2022)Normal forms of conditional knowledge bases respecting system P-entailments and signature renamingsAnnals of Mathematics and Artificial Intelligence10.1007/s10472-021-09745-390:2-3(149-179)Online publication date: 1-Mar-2022
  • (2020)Normal Forms of Conditional Knowledge Bases Respecting Entailments and RenamingsFoundations of Information and Knowledge Systems10.1007/978-3-030-39951-1_2(22-41)Online publication date: 17-Feb-2020
  • (2019)On the Antecedent Normal Form of Conditional Knowledge BasesSymbolic and Quantitative Approaches to Reasoning with Uncertainty10.1007/978-3-030-29765-7_15(175-186)Online publication date: 18-Sep-2019
  • Show More Cited By

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      cover image ACM Conferences
      SAC '19: Proceedings of the 34th ACM/SIGAPP Symposium on Applied Computing
      April 2019
      2682 pages
      ISBN:9781450359337
      DOI:10.1145/3297280
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      Published: 08 April 2019

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      Author Tags

      1. conditional logic
      2. elementwise equivalence
      3. inferential equivalence
      4. institution
      5. isomorphism
      6. knowledge base
      7. model equivalence
      8. nonmomotonic inference relation
      9. normal form

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      View all
      • (2022)Normal forms of conditional knowledge bases respecting system P-entailments and signature renamingsAnnals of Mathematics and Artificial Intelligence10.1007/s10472-021-09745-390:2-3(149-179)Online publication date: 1-Mar-2022
      • (2020)Normal Forms of Conditional Knowledge Bases Respecting Entailments and RenamingsFoundations of Information and Knowledge Systems10.1007/978-3-030-39951-1_2(22-41)Online publication date: 17-Feb-2020
      • (2019)On the Antecedent Normal Form of Conditional Knowledge BasesSymbolic and Quantitative Approaches to Reasoning with Uncertainty10.1007/978-3-030-29765-7_15(175-186)Online publication date: 18-Sep-2019
      • (2019)Systematic Generation of Conditional Knowledge Bases up to Renaming and EquivalenceLogics in Artificial Intelligence10.1007/978-3-030-19570-0_18(279-286)Online publication date: 6-May-2019

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