T. Meyer. Basic infobase change. Studia Logica, 67:215--242, 2001.  Home/Search   Document Details and Download   Summary   Related Articles   Check

....beliefs then the resulting belief set is maximal. These impossibility results about iterated revision in the usual AGM framework can be seen as a justification for the increase in representational complexity that shows up when one goes from AGM to iterated belief revision frameworks (see e.g. [7, 15, 18, 13, 17, 4]) Instead of flat belief sets (alias sets of interpretations) the latter work with epistemic states, that can be represented by preorders on interpretations. The paper is organized as follows. In section 2 we give some definitions and notations. In section 3 we consider the Darwiche and ....

T. Meyer. Basic infobase change. Studia Logica, 67:215--242, 2001.

....that the 3rd and 4th Darwiche Pearl postulates are valid. Like others we feel that the 2nd postulate is too strong. The results in this paper provide a weaker, and, we think, acceptable alternative to the 2nd postulate. We are also of the opinion that the 1st Darwich Pearl postulate is too strong ([14] provides examples to back up this claim) We adopt the basic setting in which belief change is performed on epistemic states, from which a total preorder on valuations and a knowledge base can be extracted. We provide a set of reformulated AGM postulates for belief change on epistemic states and ....

Thomas Meyer, `Basic Infobase Change', in Advanced Topics in Artificial Intelligence, ed., Norman Foo, volume 1747 of Lecture Notes In Artificial Intelligence, pp. 156--167, Berlin, (1999). Springer-Verlag.

....Pareto minimal base revisions. And unlike in the case of theories, consistent retraction minimal contractions do not lead to a deflnite belief about every possible assertion. A sample of papers on base revision with further references is (Nebel 1994) Nebel 1989) Hansson 1993) Hansson 1998) (Meyer 1999). Update:Abandoning Retraction Minimality. Let us return to modelling the agent s beliefs by logically closed theories. In that case the aim of minimizing retractions causes the di culty that it leads to complete beliefs, at least when formulated as the directive to choose retraction minimal ....

Meyer, T. (1999). Basic infobase change. In N. Foo (Ed.), Advanced Topics in Artiflcial Intelligence, pp. 156-167. Berlin: SpringerVerlag.

....approaches we focus on the merging of epistemic states, not knowledge bases. We construct a number of plausible merging operations and measure them against various properties that merging operations ought to satisfy. Finally, we discuss the connection between merging and the use of infobases [9], 10] I Introduction To be able to operate in its environment it is necessary for an intelligent agent to have a consistent view of the world. This demand is often complicated by the fact that such agents receive conflicting pieces of information from different sources. The process of ....

....[5] This is followed, in section 3, by a description of our framework for the merging of epistemic states. In section 4 we construct a number of merging operations and show how they measure up to proposed properties of merging. Section 5 discusses links between merging and the infobases of Meyer [9]. We assume a finitely generated propositional language L closed under the usual propositional connectives, and with a classical model theoretic semantics. U is the set of interpretations of L and M(a) is the set of models of a 6 L. Classical entailment is denoted by . We use U to denote the ....

[Article contains additional citation context not shown here]

Thomas Meyer. Basic Infobase Change. In Norman Foo, editor, Advanced Topics in Artificial Intelligence, volume 1747 of Lecture Notes In Artificial Intelligence, pages 156-167, Berlin, 1999. Springer-Verlag.

....7 is denoted by 89 . Similarly, the multiset of disbeliefs contained in 7 is denoted by . In section 5 the results obtained in this section will be applied to ranked information states. One way of dealing with inconsistent beliefs of equal reliability is to employ the infobases of Meyer [13, 14]. An infobase is a finite multiset of sentences. 1 Intuitively an infobase is a structured representation of the beliefs of an agent with a foundational flavour. It is assumed that every belief in an infobase is obtained independently. Meyer exploits the structure of infobases to generate total ....

....from the total preorders on . Proposition 5.2 Let Q be a knowledge base. 8 1. Let u be an AGM belief revision operation u , and let be the total preorder on corresponding to u and Q . Now construct an infobase 8 such that I . This is always possible. See [13]. Then Qu 2 iff 2 is rank entailed by ] 62 65986 1 65986 9999 999 . 2. Let x be an AGM belief contraction operation x , and let be the total preorder corresponding to x and Q . Now construct an infobase 8 such that I . Again, this is always possible. See ....

[Article contains additional citation context not shown here]

Thomas Meyer. Basic Infobase Change. In Norman Foo, editor, Advanced Topics in Artificial Intelligence, volume 1747 of Lecture Notes In Artificial Intelligence, pages 156--167, Berlin, 1999. SpringerVerlag.

....is denoted by ; Similarly, the multiset of disbeliefs contained in : is denoted by a . In section 5 the results obtained in this section will be applied to ranked information states. One way of dealing with inconsistent beliefs of equal reliability is to employ the infobases of [Meyer, 1999; Meyer et al. 2000] An infobase is a finite multiset of sentences. 1 Intuitively an infobase is a structured representation of the beliefs of an agent with a foundational flavour. It is assumed that every belief in an infobase is obtained independently. Meyer exploits the structure of ....

....can be obtained from the total preorders on . Proposition 5.2 Let T be a knowledge base. 1. Let be an AGM belief revision operation , and let be the total preorder on corresponding to and T . Now construct an infobase ; such that . This is always possible. See [Meyer , 1999] . Then Tl F 5 iff 5 is rank entailed by B KJ s) j ] Kwk 1 . 2. Let be an AGM belief contraction operation , and let be the total preorder corresponding to and T . Now construct an infobase ; such that ns . Again, this is always possible. See ....

[Article contains additional citation context not shown here]

Thomas Meyer. Basic Infobase Change. In Norman Foo, editor, Advanced Topics in Artificial Intelligence, volume 1747 of Lecture Notes In Artificial Intelligence, pages 156--167, Berlin, 1999. Springer-Verlag.

....by BA . Similarly, the multiset of disbeliefs contained in is denoted by C A . In section 5 the results obtained in this section will be applied to ranked information states. One way of dealing with inconsistent beliefs of equal reliability is to employ the infobases of Meyer et al. [16, 17]. An infobase is a finite multiset of sentences. 1 Intuitively an infobase is a structured representation of the beliefs of an agent with a foundational flavour. It is assumed that every belief in an infobase is obtained independently. Meyer exploits the structure of infobases to generate total ....

....can be obtained from the total preorders on . Theorem 5.1 Let V be a knowledge base. 1. Let z be an AGM belief revision operation z , and let be the total preorder on corresponding to z and V . Now construct an infobase such that B M . This is always possible. See [16]. Then V4zQ i : iff : is rank entailed by 68 11302 2 11302 090 . 2. Let be an AGM belief contraction operation , and let be the total preorder corresponding to and V . Now construct an infobase such that s M . Again, this is always possible. See [16] ....

[Article contains additional citation context not shown here]

Thomas Meyer. Basic Infobase Change. In Norman Foo, editor, Advanced Topics in Artificial Intelligence, volume 1747 of Lecture Notes In Artificial Intelligence, pages 156--167, Berlin, 1999. Springer-Verlag.

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