README Ronald L. Rivest and Emily Shen May 22, 2010 This is about material posted in the directory: http://people.csail.mit.edu/rivest/gt This is the README file for the code and experimental results for the GT Voting System, as described in: "An Optimal Single-Winner Preferential Voting System Based on Game Theory" by Ronald L. Rivest and Emily Shen This paper is posted on Rivest's publication page: http://people.csail.mit.edu/rivest/publications.html as well as being given in this directory. (The former may be more up-to-date.) This directory contains the following files: README This file. vs.py The main voting system program, including code for reading election profiles, computing winners according to various voting systems, and comparing various voting systems to each other. Written in python (tested in python 2.6). It requires game_cvxopt.py . It can be run on an election profile, as python vs.py data/ex_15.txt or used to compare various voting systems on simulated data, as python vs.py -compare game_cvxopt.py This is a python module that solves two-person zero-sum games, using the CVXOPT package (which must be loaded separately; see http://abel.ee.ucla.edu/cvxopt/ ). It contains an "LP"-based solver, which returns *some* optimal mixed strategy, and also a "QP"-based solver, which returns the unique *balanced* optimal mixed strategy (minimizing sum of squares). This module is called by vs.py. data This is a subdirectory containing various sample election profiles as ".txt" files, and also the corresponding margin matrices (as ".margin" files) experiment5 This directory contains the code and output for the experiment reported in our paper. gtlp.m Matlab code for solving two-person zero-sum game using LP solver. (Can be run on data available in a ".margin" file.) Returns *some* optimal mixed strategy. Not used for the results in our paper, but might be of interest to some folks. gtqp.m Matlab code for solving two-person zero-sum game using QP solver. (Can be run on data available in a ".margin" file.) Returns the unique optimal *balanced* mixed strategy (minimizing sum of squares). Not used for the results in our paper, but might be of interest to some folks. YYYY-MM-DD-RivestShen-AnOptimalSingleWinnerPreferentialVotingSystemBasedOnGameTheory_conf.pdf YYYY-MM-DD-RivestShen-AnOptimalSingleWinnerPreferentialVotingSystemBasedOnGameTheory_full.pdf latest_full.pdf latest_conf.pdf The paper describing the GT voting system; conference and full versions. (Several versions may be present, with different dates and lengths...)