In a recent paper [“Paretian Welfare Judgements and Bergsonian Social Choice,” Economic Journal, Vol. 109, 1999, pp. 204-220], Suzumura proposed a possible way of relating the two schools of “new” welfare economics. According to his proposal, the logical possibility of the Paretian “new” welfare economics can be reduced to the constrained dual choice-functional recoverability of the Pareto-comp...

The main goal of this paper is to describe a new semantic for conditional independence in terms of no double counting of uncertain evidence. For ease of exposition, we use probability calculus to state all results. But the results generalize easily to any calculus that fits in the framework of valuation-based systems. Thus, the results described in this paper apply also, for example, to Dempste...

Many physical theories accurately predict which events are possible and which are not, or – in situations where probabilistic (e.g., quantum) effects are important – predict the probabilities of different possible outcomes. At first glance, it may seem that this probabilistic information is all we need. We show, however, that to adequately describe physicists’ reasoning, it is important to also...

We consider the problem of manipulation of elections using positional voting rules under Impartial Culture voter behaviour. We consider both the logical possibility of coalitional manipulation, and the number of voters that must be recruited to form a manipulating coalition. It is shown that the manipulation problem may be well approximated by a very simple linear program in two variables. This...

Individuals working in groups often egocentrically believe they have contributed more of the total work than is logically possible. Actively considering others’ contributions effectively reduces these egocentric assessments, but this research suggests that undoing egocentric biases in groups may have some unexpected costs. Four experiments demonstrate that members who contributed much to the gr...

The motivation of possibility theory is to represent the imprecision intrinsic in natural language, in particular in expressions of the form x is R. A suitable topos of presheaves, i.e. an extension of classical set theory, is presented where sets of the form {x : x is R} can be constructed with x is R having the meaning given in possibility theory. The aim of the paper is to give an explicit m...

Possibilistic networks offer a qualitative approach for modeling epistemic uncertainty. Their practical implementation requires the specification of conditional possibility tables, as in the case of Bayesian networks for probabilities. This paper presents the possibilistic counterparts of the noisy probabilistic connectives (and, or, max, min, . . . ). Their interest is illustrated on an exampl...

We present a way of classifying the logically possible ways out of Gärdenfors’ inconsistency or triviality result on belief revision with conditionals. For one of these ways—conditionals which are not descriptive but which only have an inferential role as being given by the Ramsey test—we determine which of the assumptions in three different versions of Gärdenfors’ theorem turn out to be false....

1 Epistemic Possibility and Other Types of Possibility There is a lot that we don’t know. That means that there are a lot of possibilities that are, epistemically speaking, open. For instance, we don’t know whether it rained in Seattle yesterday. So, for us at least, there is an epistemic possibility where it rained in Seattle yesterday, and one where it did not. It’s tempting to give a very si...

The problem of expert opinions representation and aggregation has long been adressed in the only framework of probability theory. Nevertheless, recent years have witnessed many proposals in other uncertainty theories (possibility theory, evidence theory, imprecise probabilities). This paper casts the problem of aggregating expert opinions in a common underlying framework and shows how uncertain...