Manipulation by Merging and Annexation in Weighted Voting Games

Abstract

The problem of manipulation in voting is fundamental and hasreceived attention in recent research in game theory. In this paper, we considertwo cases of manipulation in weighted voting games done by mergingof coalitions into single players and by annexation of a part or all of thevoting weights of another player viewed from two perspectives: of the effectof swings of players and of the role of the Banzhaf power index. We provetwo theorems for manipulation by merging and annexation, and show severalattractive properties in these two processes.ACM Computing Classification System (1998): J.4, I.2.1.