On Fan’s Minimax Inequality

We study Fan’s minimax inequality minygCsupxgCf x, y.FsupxgC f x, x., under different assumptions on f and C in locally convex topological vector spaces. The main generalization is the weaking of ‘‘convex’’ to ‘‘acyclic.’’ The aim of this paper is to develop as consequence of several fixed point theorems and coincidence theorems a variety of existence results relevant to minimax inequalities. As an application, some variational inequalities are deduced without monotonicity nor coercivity.