Simons

Stephen Simons : Convergence, Minimax and Monotonicity


In the first lecture, we prove without measure theory a version of Fatou's lemma for continuous functions on [0,1], using only that the uniform limit of continuous functions is continuous, and that every continuous function on [0,1] attains its maximum. The proof depends on an eigenvector property of a certain family of matrices, and can be adapted to prove a result on convergence in a general Banach space. In the second talk, we show how a generalization of the Hahn-Banach theorem due to Mazur and Orlicz can be used to prove a classical minimax theorem, and we also show the connection between minimax theorems and weak compactness in a Banach space. In the remaining three talks, we define monotone and maximal monotone multifunctions on a Banach space, and show how the minimax theorem can be used to prove a number of results about these multifunctions.

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