Commit 2024-03-12 19:39 f070f429

feat: define quasispectrum for non-unital algebras (#11219) This defines the quasispectrum of an element a : A where A is a non-unital R-algebra. When A is unital and R is a semifield, then quasispectrum R a = spectrum R a ∪ {0}. The definition proceeds via quasiregular elements, which are also defined herein. The quasispectrum will serve as the domain of the continuous functions appearing in the continuous functional calculus for non-unital algebras.