Arrow's original proof of his impossibility theorem proceeded in two steps: showing the existence of a decisive voter, and then showing that a decisive voter is a dictator. Barbera replaced the decisive voter with the weaker notion of a pivotal voter, thereby shortening the first step, but...

It is shown that concept lattices can be attached in a natural way to any voting protocol. The concept lattices of some voting protocols that are solvable with respect to some prominnent solution concepts and outcome-efficient are studied: it is proved that they typically amount to chains

Based on the experiences of Colombia, Brazil and Bolivia, the paper proposes a general analytical framework for participatory mechanisms. The analysis is oriented to detect the incentives in each system and the ethics and behavior sustaining them. It investigates about the sustainability of...

This paper identifies the necessary and sufficient condition for the transitivity of the majority rule when individuals are never indifferent between two distinct alternatives (linear domain). By introducing the concept of the relevant population for each set of alternatives, a unique condition...

In this brief comment, the public choice theory aims to distinguish the dilemmas and conflicts in formal and empirical. The hypothesis argues that the reality more complex than the principles of choice of Pareto and Liberalism*. Both the ethics and politics are taking decisions that are not...

This introduces the symposium on judgment aggregation. The theory of judgment ag­gregation asks how several individuals' judgments on some logically connected propo­sitions can be aggregated into consistent collective judgments. The aim of this intro­duction is to show how ideas from the...

In general in an organization whose system of governance involves weighted voting, a member's weight in terms of the number of votes and the formal power it represents differ. Power indices provide a means of analyzing this difference. The paper uses new algorithms for computing power indices...

In this paper, the authors investigate judgment aggregation by assuming that some formulas of the agenda are singled out as premisses, and the Independence condition (formula-wise aggregation) holds for them, though perhaps not for others.

A society needs to decide which issues (laws, public projects, public facilities, etc.) in an agenda to accept. The decision can be any subset of the agenda but must reflect the preferences of its members, which are assumed to be ¡°separable weak orderings¡±. We characterize a family of...

We formalize a notion of conditionally decisive powers of which the exercise depends on social consent. Decisive powers, or the so-called libertarian rights, are examples and much weaker forms of powers are covered by our notion. Main results provide an axiomatic characterization for existence...