Square roots and quasi-square roots in locally multiplicatively convex algebras
Square roots of elements with an unbounded spectrum
Subsets of nonempty joint spectrum in topological algebras
We give a necessary and a sufficient condition for a subset of a locally convex Waelbroeck algebra to have a non-void left joint spectrum In particular, for a Lie subalgebra we have if and only if generates in a proper left ideal. We also obtain a version of the spectral mapping formula for a modified left joint spectrum. Analogous theorems for the right joint spectrum and the Harte spectrum are also valid.
Symbolic calculus on weighted group algebras
The group of invertible elements in a Banach algebra
The holomorphic functional calculus as an operational calculus
The monogenic functional calculus
A study is made of a symmetric functional calculus for a system of bounded linear operators acting on a Banach space. Finite real linear combinations of the operators have real spectra, but the operators do not necessarily commute with each other. Analytic functions of the operators are formed by using functions taking their values in a Clifford algebra.
The Relative Spectrum of Elements in a Real Banach Algebra.
The Taylor spectrum and quotient Banach spaces
О функциях от операторов
Структурный пучок банаховой алгебры
Функциональное исчисление для почти изометрических операторов