Pseudo-contractive mappings and the Leray-Schauder boundary condition
Let be a real Banach space. A multivalued operator from into is said to be pseudo-contractive if for every in , , and all , . Denote by the set . Suppose every bounded closed and convex subset of has the fixed point property with respect to nonexpansive selfmappings. Now if is a Lipschitzian and pseudo-contractive mapping from into the family of closed and bounded subsets of so that the set is bounded for some and some , then has a fixed point in .
Consider the Mann iteration for a nonexpansive mapping defined on some subset of the normed space . We present an innovative proof of the Ishikawa almost fixed point principle for nonexpansive mapping that reveals deeper aspects of the behavior of the process. This fact allows us, among other results, to derive convergence of the process under the assumption of existence of an accumulation point of .
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