Journal of Logic, Language and Information

, Volume 8, Issue 2, pp 187–203

Reasoning about Minimal Knowledge in Nonmonotonic Modal Logics

  • Riccardo Rosati

DOI: 10.1023/A:1008277218820

Cite this article as:
Rosati, R. Journal of Logic, Language and Information (1999) 8: 187. doi:10.1023/A:1008277218820


We study the problem of embedding Halpern and Moses's modal logic of minimal knowledge states into two families of modal formalism for nonmonotonic reasoning, McDermott and Doyle's nonmonotonic modal logics and ground nonmonotonic modal logics. First, we prove that Halpern and Moses's logic can be embedded into all ground logics; moreover, the translation employed allows for establishing a lower bound (Π3p) for the problem of skeptical reasoning in all ground logics. Then, we show a translation of Halpern and Moses's logic into a significant subset of McDermott and Doyle's formalisms. Such a translation both indicates the ability of Halpern and Moses's logic of expressing minimal knowledge states in a more compact way than McDermott and Doyle's logics, and allows for a comparison of the epistemological properties of such nonmonotonic modal formalisms.

Knowledge representation nonmonotonic reasoning epistemic modal logics computational complexity 

Copyright information

© Kluwer Academic Publishers 1999

Authors and Affiliations

  • Riccardo Rosati
    • 1
  1. 1.Dipartimento di Informatica e SistemisticaUniversità di Roma “La Sapienza”RomaItaly (E-mail

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