A numerical range for nonlinear operators in smooth Banach spaces
The author defines and discusses a numerical range for nonlinear operators in smooth Banach spaces, and studies its relations with certain spectral sets. He shows, in particular, that the spectrum of a Lipschitz operator in the sense of \textit{R. I. Kachurovskij} [Dokl. Akad. Nauk SSSR 188, 274-277 (1969; Zbl 0197.40402)] is contained in the smallest Jordan domain containing the numerical range.
scientific article; zbMATH DE number 889006
scientific article