RELAÇÕES ENTRE DIFERENTES TIPOS DE FUNÇÕES DE CONTRACÇÃO MÚLTIPLA DE CRENÇAS

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Epistemic entrenchment-based multiple contractions

Publication . Fermé, Eduardo; Reis, Maurício D. L.

In this article we present a new class of multiple contraction functions—the epistemic entrenchment-based multiple contractions—which are a generalization of the epistemic entrenchment-based contractions (Gardenfors, 1988; G ¨ ardenfors & Makinson, 1988) to the case of ¨ contractions by (possibly nonsingleton) sets of sentences and provide an axiomatic characterization for that class of functions. Moreover, we show that the class of epistemic entrenchment-based multi ple contractions coincides with the class of system of spheres-based multiple contractions introduced in Ferme & Reis (2012).

2013Journal article

Open access

System of spheres-based multiple contractions

Publication . Fermé, Eduardo; Reis, Maurício D. L.

We propose a new class of multiple contraction operations — the system of spheres-based multiple contractions — which are a generalization of Grove’s system of spheres-based (singleton) contractions to the case of contractions by (possibly non-singleton) sets of sentences. Furthermore, we show that this new class of functions is a subclass of the class of the partial meet multiple contractions.

2011Journal article

Open access

Possible worlds semantics for partial meet multiple contraction

Publication . Reis, Maurício D. L.; Fermé, Eduardo

In the logic of theory change, the standard model is AGM, proposed by Alchourrón et al. (J Symb Log 50:510–530, 1985). This paper focuses on the extension of AGM that accounts for contractions of a theory by a set of sentences instead of only by a single sentence. Hansson (Theoria 55:114–132, 1989), Fuhrmann and Hansson (J Logic Lang Inf 3:39–74, 1994) generalized Partial Meet Contraction to the case of contractions by (possibly non-singleton) sets of sentences. In this paper we present the possible worlds semantics for partial meet multiple contractions.

2011Journal article

Open access