Approximation by unitaries with finite spectrum in purely infinite \(C^*\)-algebras
The author proves that a unital purely infinite simple \(C^*\)-algebra has \(C^*\)-exponential rank at most \(1+ \varepsilon\), and therefore has the property weak (FU): Every element of the identity component of the unitary group is norm limit of unitaries with finite spectrum. He also proves the appropriate modification of this statement for nonunital algebras.
scientific article; zbMATH DE number 599751