This paper is a revised version based on two of my earlier papers Lahiri (1989c) and Lahiri (1990). For useful suggestions and discussions I am grateful to Jim Jordan, T.Parthasarathy, Prakash Chander, Arunava Sen and the participants of the 1990 International Conference of Game Theory and Its Applications to Economic held at Indian Statistical Institute (New Delhi). In particular this paper has benefited from the comments of Hans Peters and Mamoru Kaneko.