NOVA Laboratory for Computer Science and Informatics

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Publications

Iterated belief change: the case of expansion into inconsistency

Publication . Fermé, Eduardo; Wassermann, Renata

Constructing models that allow iterated changes is one of the most studied problems in the literature on belief change. However, up to now, iteration of expansion was only studied as a special case of consistent revision and, as far we know, there is no work in the literature that deals with expansions into inconsistency in a supraclassical framework. In this paper, we provide a semantics for iterated expansion, as well as its axiomatic characterization. We extend the model to two well-known families of iterated belief change (natural and lexicographic). Iteration of expansion can be combined with existent models of iteration of revision and contraction. Since we are able to accommodate different inconsistent belief states, iteration of expansion allows us to define new belief change functions that are currently only defined for belief bases: semi revision, external revision, as well as consolidation.

2017Conference object

Open access

How to construct remainder sets for paraconsistent revisions: preliminary report

Publication . Testa, Rafael; Fermé, Eduardo; Garapa, Marco; Reis, Maurício

Revision operation is the consistent expansion of a theory by a new belief-representing sentence. We consider that in a paraconsistent setting this desideratum can be accomplished in at least three distinct ways: the output of a revision op eration should be either non-trivial or non-contradictory (in general or relative to the new belief). In this paper those dis tinctions will be explored in the constructive level by showing how the remainder sets could be refined, capturing the key concepts of paraconsistency in a dynamical scenario. These are preliminaries results of a wider project on Paraconsistent Belief Change conduced by the authors.

2018Conference object

Open access

A semantic perspective on belief change in a preferential non-monotonic framework

Publication . Casini, Giovanni; Fermé, Eduardo; Meyer, Thomas; Varzinczak, Ivan

Belief change and non-monotonic reasoning are usually viewed as two sides of the same coin, with results showing that one can formally be defined in terms of the other. In this paper we investigate the integration of the two formalisms by studying belief change for a (preferential) non-monotonic framework. We show that the standard AGM approach to be lief change can be transferred to a preferential non-monotonic framework in the sense that change operations can be defined on conditional knowledge bases. We take as a point of depar ture the results presented by Casini and Meyer (2017), and we develop and extend such results with characterisations based on semantics and entrenchment relations, showing how some of the constructions defined for propositional logic can be lifted to our preferential non-monotonic framework.

2018Conference object

Open access

Using decision theory for analyzing enrollment in a scientific study in the health area

Publication . Pereira, Fábio; Fermé, Eduardo

This article explores the current literature about the factors that lead people to enroll in a scientific study in the area of health. Recruitment of participants has been shown to be a problem with the number of participants willing to participate decreasing widely. For this reason, it is important to understand how and why people make the decision to participate in a scientific study, in order to develop mechanisms that counteract this tendency. For that purpose, a review of current literature was conducted and the evidence was related with decision theory. The goal is to understand how the decision process to participate in a study occurs and which actions can be taken to maximize the recruitment process.

2018Conference object

Open access

Studies in credibility: limited base revision

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

In this paper we present axiomatic characterizations for several classes of credibility-limited base revision functions and establish the interrelation among those classes. We also propose and axiomatically characterize two new base revision functions.

2018Conference object

Open access