Operator algebras of functions

Stable Ranks of Banach Algebras of Operator-valued H Functions

Let E be an infinite-dimensional Hilbert space, and let H L(E) denote the Banach algebra of all functions f : D → L(E) that are holomorphic and bounded, equipped with the supremum norm ‖f‖∞ := supz∈D ‖f(z)‖L(E), f ∈ H ∞ L(E). We show that the Bass and topological stable ranks of H L(E) are infinite. If S is an open subset of T, then let A S L(E) denote the subalgebra of H L(E) of all functions ...

Operator Algebras

Notice that the left-hand side of the third equation is the sum of the left-hand sides of the first two. As a result, no solution to the system exists unless a + b = c. But if a + b = c, then any solution of the first two equations is also a solution of the third; and in any linear system involving more unknowns than equations, solutions, when they exist, are never unique. In the present case, ...

Operator Theory and Operator Algebras

Löwner's Operator and Spectral Functions in Euclidean Jordan Algebras

We study analyticity, differentiability, and semismoothness of Löwner’s operator and spectral functions under the framework of Euclidean Jordan algebras. In particular, we show that many optimization-related classical results in the symmetric matrix space can be generalized within this framework. For example, the metric projection operator over any symmetric cone defined in a Euclidean Jordan a...

Automorphisms of Operator Algebras