The existence of maximal elements for binary preference relations is analyzed without imposing transitivity or convexity conditions. From each preference relation a new acyclic relation is defined in such a way that some maximal elements of this new relation characterize maximal elements of the...

Choice functions on tournaments always select the maximal element (Condorcet winner), provided they exist, but this property does not hold in the more general case of weak tournaments. In this paper we analyze the relationship between the usual choice functions and the set of maximal elements in...

The problem of sharing a cost M among n individuals, identified by some characteristic ci∈R+, appears in many real situations. Two important proposals on how to share the cost are the egalitarian and the proportional solutions. In different situations a combination of both distributions...

A new voting rule for electing committees is described. Specifically, we use approval balloting and propose a voting procedure guaranteeing that if a committee representing (in a determined proportion) all voters exists, then the selected committee has to represent all voters at least in the...

In this paper we consider convex combinations of matrices that arise in the study of distribution problems and analyse the properties of Perron's eigenvalue, and its associated positive eigenvector. We prove that the components in the (normalized) associated positive eigenvector have a monotone...

If we analyze the notion of stability (von Neumann and Morgenstern, 1944) it seems a desirable property to be fulfilled by any choice function. Paradoxically, the usual Condorcet choice functions (maximal set, top cycle, uncovered set, minimal covering, ...) are not stable in the VNM sense. In...

In 1950, Nash's seminal paper introduced the axiomatic approach to the analysis of bargaining situations. Since then, many bargaining solutions have appeared and been axiomatically analyzed. The fact that agents, when face a bargaining problem, can come up with different solution concepts (that...

We consider a cost sharing problem, where each individual is identi ed by a characteristic (a positive real number) ci: The two main positions on how to share a common cost M are the Egalitarian and the Proportional solutions. These solutions can be obtained as the Perron's eigenvectors (right...

The notion of a stable set (introduced by von Neumann and Morgenstern, 1944) is an important tool in the field of Decision Theory. Since then, some alternative definitions have appeared in the literature: the admissible set (Kalai and Schmeidler, 1977), the generalized stable set (van Deemen,...

The notion of a stable set (introduced by von Neumann and Morgenstern, 1944) is an important tool in the field of Decision Theory. However, stable sets may fail to exist. Other stability notions have been introduced in the literature in order to solve the non-existence problem. We propose a new...