Stable flows generalize the well-known concept of stable matchings to markets in which transactions may involve several agents, forwarding flow from one to another. An instance of the problem consists of a capacitated directed network in which vertices express their preferences over their...

An instance of the marriage problem is given by a graph G together with, for each vertex of G, a strict preference order over its neighbors. A matching M of G is popular in the marriage instance if M does not lose a head-to-head election against any matching where vertices are voters. Every...

Our input is a complete graph G on n vertices where each vertex has a strictranking of all other vertices in G. The goal is to construct a matching in G that is "globallystable" or popular. A matching M is popular if M does not lose a head-to-head election againstany matching M': here each...

Focusing on the testable implications on the equilibrium manifold, we show that the rationalizability problem is NP-complete. Subsequently, we present an integer programming (IP) approach to characterizing general equilibrium models. This approach avoids the use of the Tarski-Seidenberg...

We consider the class of (finite) spatial games. We show that the problem of determining whether there exists a Nash equilibrium in which each player has a payoff of at least k is NP-complete as a function of the number of players. Copyright Springer-Verlag Berlin/Heidelberg 2004

In this paper we analyse the portfolio selectionproblem with minimum transactionlots in the context of non-expected utility theory. We assume that the decisionmaker ranks the alternatives by using a specific DualExpectedUtility. This functionallows portfolio values less or equal a fixed...

In this paper we study hedonic games where each player views every other player either as a friend or as an enemy. Two simple priority criteria for comparison of coalitions are suggested, and the corresponding preference restrictions based on appreciation of friends and aversion to enemies are...

In this paper we give an overview of various methods used to study cooperation within a set of players. Besides the classical games with transferable utility and games without transferable utility, recently new models have been proposed: the coalition formation games. In these, each player has...

Electronic voting systems are no longer a theoretical matter and they have been successfully used in elections and referendums in some countries. With such systems some problems of paper ballots can be eliminated easily. However, these systems have their own security problems. In this article,...