Unitary Banach algebras

• Autorzy: Julio Becerra Guerrero , Simon Cowell , Ángel Rodríguez Palacios , Geoffrey V. Wood
• Języki publikacji: EN

Abstrakty

EN

In a Banach algebra an invertible element which has norm one and whose inverse has norm one is called unitary. The algebra is unitary if the closed convex hull of the unitary elements is the closed unit ball. The main examples are the C*-algebras and the ℓ₁ group algebra of a group. In this paper, different characterizations of unitary algebras are obtained in terms of numerical ranges, dentability and holomorphy. In the process some new characterizations of C*-algebras are given.

Kategorie tematyczne

• 46B04: Isometric theory of Banach spaces
• 46H05: General theory of topological algebras
• 43A20: L 1 -algebras on groups, semigroups, etc.

• Wydawca: Institute of Mathematics Polish Academy of Sciences
• Czasopismo: Studia Mathematica
• Rocznik: 2004
• Tom: 162
• Numer: 1
• Strony: 25-51

Daty

wydano

2004

Twórcy

autor

Julio Becerra Guerrero

• Departamento de Matemática Aplicada, Facultad de Ciencias, Universidad de Granada, 18071-Granada, Spain

autor

Simon Cowell

• Department of Mathematics, University of Wales Swansea, Swansea SA2 8PP, Wales, UK

autor

Ángel Rodríguez Palacios

• Departamento de Análisis Matemático, Facultad de Ciencias, Universidad de Granada, 18071-Granada, Spain

autor

Geoffrey V. Wood

• Department of Mathematics, University of Wales Swansea, Swansea SA2 8PP, Wales, UK

Identyfikatory

DOI

10.4064/sm162-1-3