Topological essentiality and fixed point theory
The authors show that if \(G\) is essential and \(F\cong G\), then \(F\) is essential under certain conditions. They here discuss upper semi-continuous maps and one-set contractive demicompact maps. Some perturbations of linear Fredholm maps of index zero are also discussed.
perturbation of linear Fredholm maps of index zero
scientific article; zbMATH DE number 1394536