Spectra of normal composition operators on \(L^ 2\)-spaces
Let \(C_ T\) be a composition operator on \(L^ 2(\lambda)\), where \(\lambda\) is a sigma-finite measure on a measurable space (X,\({\mathcal S})\). The spectra of normal composition operators are determined in this note. A sufficient condition for the spectrum of a normal composition operator to have cyclic symmetry is obtained. Weyl spectra of normal composition operators are also obtained.
scientific article; zbMATH DE number 3929763