164 research outputs found
Coalitional power indices applied to voting systems
We describe voting mechanisms to study voting systems. The classical power indices applied to simple games
just consider parties, players or voters. Here, we also consider games with a priori unions, i.e., coalitions
among parties, players or voters. We measure the power of each party, player or voter when there are coalitions
among them. In particular, we study real situations of voting systems using extended Shapley–Shubik
and Banzhaf indices, the so-called coalitional power indices. We also introduce a dynamic programming to
compute them.Peer ReviewedPostprint (published version
A Fibonacci sequence for linear structures with two types of components
We investigate binary voting systems with two types of voters and a hierarchy
among the members in each type, so that members in one class have more
influence or importance than members in the other class. The purpose of this
paper is to count, up to isomorphism, the number of these voting systems for an
arbitrary number of voters. We obtain a closed formula for the number of these
systems, this formula follows a Fibonacci sequence with a smooth polynomial
variation on the number of voters.Comment: All the results contained in this file are included in a paper
submitted to Annals of Operations Research in October, 2008 on ocasion of the
Conference on Applied Mathematical Programming and Modelling, that held in
Bratislava in May, 200
An Efficient generic algorithm for the generation of unlabelled cycles
In this report we combine two recent generation algorithms to obtain a
new algorithm for the generation of unlabelled cycles. Sawada's
algorithm lists all k-ary unlabelled cycles with fixed
content, that is, the
number of occurences of each symbol is fixed and given a priori.
The other algorithm, by the authors, generates all
multisets of objects with given total size n from any admissible
unlabelled class A. By admissible
we mean that the class can be specificied using atomic classes,
disjoints unions, products, sequences, (multi)sets, etc.
The resulting algorithm, which is the main contribution of this paper,
generates all cycles of objects with given total size n from any
admissible class A. Given the
generic nature of the algorithm, it is suitable for inclusion in
combinatorial libraries and for rapid prototyping. The new algorithm
incurs constant amortized time per generated cycle, the constant only
depending in the class A to which the objects in the cycle belong.Postprint (published version
Combinatorial structures to modeling simple games and applications
We connect three different topics: combinatorial structures, game theory and chemistry. In particular, we establish the bases to represent some simple games, defined as influence games, and molecules, defined from atoms, by using combinatorial structures. First, we characterize simple games as influence games using influence graphs. It let us to modeling simple games as combinatorial structures (from the viewpoint of structures or graphs). Second, we formally define molecules as combinations of atoms. It let us to modeling molecules as combinatorial structures (from the viewpoint of combinations). It is open to generate such combinatorial structures using some specific techniques as genetic algorithms, (meta-)heuristics algorithms and parallel programming, among others.Peer ReviewedPostprint (published version
Combinatorial structures to construct simple games and molecules
We connect three different topics: combinatorial structures, game theory and chemistry. In particular, we establish the bases to represent some simple games, defined as influence games, and molecules, defined from atoms, by using combinatorial structures. First, we characterize simple games as influence games using influence graphs. It let us to modeling simple games as combinatorial structures (from the viewpoint of structures or graphs). Second, we formally define molecules as combinations of atoms. It let us to modeling molecules as combinatorial structures (from the viewpoint of combinations). It is open to generate such combinatorial structures using some specific techniques as genetic algorithms, (meta-) heuristics algorithms and parallel programming, among others.Peer ReviewedPostprint (published version
Measuring satisfaction in societies with opinion leaders and mediators
An opinion leader-follower model (OLF) is a two-action collective decision-making model for societies, in which three kinds of actors are considered:Preprin
Cooperation through social influence
We consider a simple and altruistic multiagent system in which the agents are eager to perform a collective task but where their real engagement depends on the willingness to perform the task of other influential agents. We model this scenario by an influence game, a cooperative simple game in which a team (or coalition) of players succeeds if it is able to convince enough agents to participate in the task (to vote in favor of a decision). We take the linear threshold model as the influence model. We show first the expressiveness of influence games showing that they capture the class of simple games. Then we characterize the computational complexity of various problems on influence games, including measures (length and width), values (Shapley-Shubik and Banzhaf) and properties (of teams and players). Finally, we analyze those problems for some particular extremal cases, with respect to the propagation of influence, showing tighter complexity characterizations.Peer ReviewedPostprint (author’s final draft
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