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A degree theory for a class of perturbed Fredholm maps


We define a notion of degree for a class of perturbations of nonlinear Fredholm maps of index zero between infinite-dimensional real Banach spaces. Our notion extends the degree introduced by Nussbaum for locally -contractive perturbations of the identity, as well as the recent degree for locally compact perturbations of Fredholm maps of index zero defined by the first and third authors.

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Correspondence to Pierluigi Benevieri.

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Open Access This article is distributed under the terms of the Creative Commons Attribution 2.0 International License ( ), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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Benevieri, P., Calamai, A. & Furi, M. A degree theory for a class of perturbed Fredholm maps. Fixed Point Theory Appl 2005, 659461 (2005).

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