Generalized monotonicity and strategy−proofness for non−resolute social choice correspondences

Recently there are several works which analyzed the strategy−proofness of non−resolute social choice rules such as Duggan and Schwartz (2000) and Ching and Zhou (2001). In these analyses it was assumed that individual preferences are linear, that is, they excluded indifference from individual preferences. We present an analysis of the strategy−proofness of non−resolute social choice rules when indifference in individual preferences is allowed. Following to the definition of the strategy−proofness by Ching and Zhou (2001) we shall show that a generalized version of monotonicity and the strategy−proofness are equivalent. It is an extension of the equivalence of monotonicity and the strategy−proofness for resolute social choice rules with linear individual preferences proved by Muller and Satterthwate (1980) to the case of non−resolute social choice rules with general individual preferences. I wish to thank anonymous referees for their very helpful comments. Citation: Tanaka, Yasuhito, (2001) "Generalized monotonicity and strategy−proofness for non−resolute social choice correspondences." Economics Bulletin, Vol. 4, No. 12 pp. 1−8 Submitted: August 29, 2001. Accepted: December 1, 2001. URL: http://www.economicsbulletin.com/2001/volume4/EB−01D70008A.pdf