References of "Pigozzi, Gabriella 40000533"
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See detailPremise Independence in Judgment Aggregation
Pigozzi, Gabriella UL; van der Torre, Leon UL

in Formal Models of Belief Change in Rational Agents (2007)

Judgment aggregation studies how agent opinions on logically interconnected propositions can be mapped into a collective judgment on the same propositions, and is plagued by impossibility results. In this ... [more ▼]

Judgment aggregation studies how agent opinions on logically interconnected propositions can be mapped into a collective judgment on the same propositions, and is plagued by impossibility results. In this paper we study the central notion of independence in these impossibility results. First, we argue that the distinction between the premises and conclusions play an important role in the benchmark examples of judgment aggregation. Second, we consider the notion of independence in judgment aggregation frameworks, and we observe that the distinction between premises and conclusion is not taken into account. Third, based on our analysis, we introduce independence assumptions that distinguish premises from conclusion. We show that, by introducing new operators that satisfy our independence assumptions, the problematic impossibility results no longer hold. [less ▲]

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See detailCommon Foundations for Belief Revision, Belief Merging and Voting
Gabbay, Dov M. UL; Pigozzi, Gabriella UL; Rodrigues, Odinaldo

in Formal Models of Belief Change in Rational Agents (2007)

In this paper, we consider a number of different ways of reasoning about voting as a problem of conciliating contradictory interests. The mechanisms that do the reconciliation are belief revision and be ... [more ▼]

In this paper, we consider a number of different ways of reasoning about voting as a problem of conciliating contradictory interests. The mechanisms that do the reconciliation are belief revision and be- lief merging. By investigating the relationship between different voting strategies and their associated counterparts in revision theory, we find that whereas the counting mechanism of the voting process is more easily done at the meta-level in belief merging, it can be brought to the object level in base revision. In the former case, the counting can b e tweaked according to the aggregation procedure used, whereas in base revision, we can only rely on the notion of minimal change and hence the syntactical representation of the voters’ preferences plays a crucial part in the process. This highlights the similarities between the revi sion approaches on the one hand and voting on the other, but also opens up a numb er of interesting questions. [less ▲]

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See detailJudgment Aggregation and the Problem of Truth-Tracking
Pigozzi, Gabriella UL; Hartmann, Stephan

in Proceedings of the 11th conference on Theoretical aspects of rationality and knowledge (2007)

The problem of the aggregation of consistent individual judgments on logically interconnected propositions into a collective judgment on the same propositions has recently drawn much attention. The ... [more ▼]

The problem of the aggregation of consistent individual judgments on logically interconnected propositions into a collective judgment on the same propositions has recently drawn much attention. The difficulty lies in the fact that a seemingly reasonable aggregation procedure, such as propositionwise majority voting, cannot ensure an equally consistent collective outcome. The literature on judgment aggregation refers to such dilemmas as the doctrinal paradox. Three procedures have been proposed in order to overcome the paradox: the premise-based and conclusion-based procedures on the one hand, and the fusion approach on the other hand. In this paper we assume that the decision which the group is trying to reach is factually right or wrong. Hence, the question is how good the fusion approach is in tracking the truth, and how it compares with the premise-based and conclusion-based procedures. We address these questions in a probabilistic framework and show that belief fusion does especially well for individuals with a middling competence of hitting the truth of a proposition. [less ▲]

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See detailChoosing Your Beliefs
Boella, Guido UL; Pereira, Célia Da Costa UL; Pigozzi, Gabriella UL et al

in Normative Multi-agent Systems (2007)

This paper presents and discusses a novel approach to indeterministic belief revision. An indeterministic belief revision operator assumes that, when an agent is confronted with a new piece of information ... [more ▼]

This paper presents and discusses a novel approach to indeterministic belief revision. An indeterministic belief revision operator assumes that, when an agent is confronted with a new piece of information, it can revise its belief sets in more than one way. We define a rational agent not only in terms of what it believes but also of what it desires and wants to achieve. Hence, we propose that the agent's goals play a role in the choice of (possibly) one of the several available revision options. Properties of the new belief revision mechanism are also investigated. [less ▲]

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See detailTen Philosophical Problems in Deontic Logic
Hansen, Jörg UL; Pigozzi, Gabriella UL; van der Torre, Leon UL

in Normative Multi-agent Systems (2007)

The paper discusses ten philosophical problems in deontic logic: how to formally represent norms, when a set of norms may be termed `coherent', how to deal with normative conflicts, how contrary-to-duty ... [more ▼]

The paper discusses ten philosophical problems in deontic logic: how to formally represent norms, when a set of norms may be termed `coherent', how to deal with normative conflicts, how contrary-to-duty obligations can be appropriately modeled, how dyadic deontic operators may be redefined to relate to sets of norms instead of preference relations between possible worlds, how various concepts of permission can be accommodated, how meaning postulates and counts-as conditionals can be taken into account, and how sets of norms may be revised and merged. The problems are discussed from the viewpoint of input/output logic as developed by van der Torre Makinson. We argue that norms, not ideality, should take the central position in deontic semantics, and that a semantics that represents norms, as input/output logic does, provides helpful tools for analyzing, clarifying and solving the problems of deontic logic. [less ▲]

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See detailAggregation in Multi-Agent Systems and the Problem of Truth-Tracking
Pigozzi, Gabriella UL; Hartmann, Stephan

Poster (2007)

One of the major problems that artificial intelligence needs to tackle is the combination of different and potentially conflicting sources of information. Examples are multi-sensor fusion, database ... [more ▼]

One of the major problems that artificial intelligence needs to tackle is the combination of different and potentially conflicting sources of information. Examples are multi-sensor fusion, database integration and expert systems development. In this paper we are interested in the aggregation of propositional logic-based information, a problem recently addressed in the literature on information fusion. It has applications in multiagent systems that aim at aggregating the distributed agent-based knowledge into an (ideally) unique set of propositions. We consider a group of autonomous agents who individually hold a logically consistent set of propositions. Each set of propositions represents an agent's beliefs on issues on which the group has to make a collective decision. To make the collective decision, several aggregation procedures have been proposed in the literature. Assuming that all propositions in question are factually right or wrong, we ask how good belief fusion is as a truth tracker. Will it single out the true set of propositions? And how does information fusion compare with other aggregation procedures? We address these questions in a probabilistic framework and show that information fusion does especially well for agents with a middling competence of hitting the truth of an individual proposition. [less ▲]

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See detailMerging judgments and the problem of truth-tracking
Pigozzi, Gabriella UL; Hartmann, Stephan

Scientific Conference (2006, December 07)

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See detailBelief revision, belief merging and voting
Gabbay, Dov M. UL; Pigozzi, Gabriella UL; Rodrigues, O.

in Proceedings of the Seventh Conference on Logic and the Foundations of Games and Decision Theory (LOFT06) (2006)

In belief revision, an agent is faced with the problem of choosing between several alternatives when trying to restore con- sistency to theory. Ideally, the choice process is conducted in a way that ... [more ▼]

In belief revision, an agent is faced with the problem of choosing between several alternatives when trying to restore con- sistency to theory. Ideally, the choice process is conducted in a way that verifies a number of fairness principles. On the other hand, be- lief merging concerns with the problem of determining a group’s be- liefs from individual members’ beliefs that are not always compatible with each other. Similarly, in voting systems, a social welfare func- tion takes individual preferences into account in order to produce a collective preference. Here again certain fairness principles are desir- able. In this paper, we investigate the relationship between revision, merging and voting. [less ▲]

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