Fredholm Operators and the Essential Spectrum

ISBN: 9781332906789 出版年：2016 页码：50 Martin Schechter Forgotten Books

We first give a complete treatment of Fredholm operators. Most of the results are found in the literature [4, but we have been able to substantially simplify proofs in sev eral instances. The deepest theorem we make use of is the closed graph theorem. We are able to avoid completely the concept of the opening between two subspaces.