Francois Schulz

collaborators

3 papers

math.FA2024

Banach algebra mappings preserving the invertibility of linear pencils

Francois Schulz

Let $A$ and $B$ be complex unital Banach algebras, and let $φ, ψ : A \to B$ be surjective mappings. If $A$ is semisimple with an essential socle and $φ$ and $ψ$ preserves the invert…

math.FA2024

Commutativity and orthogonality of similarity orbits in Banach algebras

Muhammad Hassen, Rudi Brits, Francois Schulz

For a semisimple unital Banach algebra $A$ over $C$ , and elements $a, b \in A,$ we show that the similarity orbits, $orb (a)$ and $orb (b)$ , over the princip…

math.FA2023

Additive spectrum preserving mappings from von Neumann algebras

Martin Mathieu, Francois Schulz

We establish Jafarian's 2009 conjecture that every additive spectrum preserving mapping from a von Neumann algebra onto a semisimple Banach algebra is a Jordan isomorphism.