This paper shows a fundamental property of vector fields representing dynamics on spaces of mixed strategies of normal form games whose zeros coincide with the Nash equilibria of the underlying games. The property shown is that the indices of components of zeros of any vector field in this class...

We extend Kohlberg and Mertens' (1986) structure theorem on the Nash correspondence to show that its graph is not only homeomorphic to the underlying space of games, but that the homeomorphism extends to the ambient space of games times strategies, thus implying the graph is unknotted. This has...