Authors:
Ramoni O. Lasisi
and
Vicki H. Allan
Affiliation:
Utah State University, United States
Keyword(s):
Agents, Manipulations, Annexation, Merging, Power indices.
Related
Ontology
Subjects/Areas/Topics:
Agents
;
Artificial Intelligence
;
Artificial Intelligence and Decision Support Systems
;
Cooperation and Coordination
;
Distributed and Mobile Software Systems
;
Enterprise Information Systems
;
Knowledge Engineering and Ontology Development
;
Knowledge-Based Systems
;
Multi-Agent Systems
;
Software Engineering
;
Symbolic Systems
Abstract:
This paper discusses weighted voting games and two methods of manipulating those games, called annexation and merging. These manipulations allow either an agent, called an annexer to take over the voting weights of some other agents in the game, or the coming together of some agents to form a bloc of manipulators to have more power over the outcomes of the games. We evaluate the extent of susceptibility to these manipulations in weighted voting games of the following prominent power indices: Shapley-Shubik, Banzhaf, and Deegan-Packel indices. We found that for unanimity weighted voting games of n agents and for the three indices: the manipulability, (i.e., the extent of susceptibility to manipulation) via annexation of any one index does not dominate that of other indices, and the upper bound on the extent to which an annexer may gain while annexing other agents is at most n times the power of the agent in the original game. Experiments on non unanimity weighted voting games suggest
that the three indices are highly susceptible to manipulation via annexation while they are less susceptible to manipulation via merging. In both annexation and merging, the Shapley-Shubik index is the most susceptible to manipulation among the indices.
(More)