## RAIRO - Theoretical Informatics and Applications

### A distributed voting scheme to maximize preferences

a1 Dept. of Mathematics and Information Technologies, University of Leoben, Austria.

a2 Dipartimento di Scienze dell'Informazione, Università degli Studi di Milano, Italy; cesa-bianchi@dsi.unimi.it

Abstract

We study the problem of designing a distributed voting scheme for electing a candidate that maximizes the preferences of a set of agents. We assume the preference of agent i for candidate j is a real number xi,j , and we do not make any assumptions on the mechanism generating these preferences. We show simple randomized voting schemes guaranteeing the election of a candidate whose expected total preference is nearly the highest among all candidates. The algorithms we consider are designed so that each agent has to disclose only a few bits of information from his preference table. Finally, in the important special case in which each agent is forced to vote for at most one candidate we show that our voting scheme is essentially optimal.

(Online publication July 20 2006)

Mathematics Subject Classification:

• 68W15;
• 91B12