The optimistic and cautious semantics for inconsistent knowledge bases

John Grant, V. S. Subrahmanian

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


We develop two alternative semantics, based on maximal consistent subsets, for knowledge bases that (possibly) contain inconsistencies. The optimistic (resp. cautious) semantics correspond to entailment in some (resp. all) maximal consistent subsets. We develop a Kripke-style model theory corresponding to these two semantics. We further extend these semantics to the case when knowledge bases contain both explicit and nonmonotonic negation. Notions of stratification and stability are defined and studied for both semantics.

Original languageEnglish (US)
Pages (from-to)37-55
Number of pages19
JournalActa Cybernetica
Issue number1
StatePublished - 1995
Externally publishedYes

ASJC Scopus subject areas

  • Software
  • Computer Science (miscellaneous)
  • Information Systems and Management
  • Theoretical Computer Science
  • Electrical and Electronic Engineering
  • Computer Vision and Pattern Recognition
  • Management Science and Operations Research


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