On Birkhoff – James and Roberts orthogonality

Abstract

In this paper we present some recent results on characterizations of the Birkhoff-James and the Roberts orthogonality in C*-algebras and Hilbert C*-modules.

Keywords

• normed linear space
• birkhoff-james orthogonality
• roberts orthogonality
• c*-algebra
• numerical range
• davis-wielandt shell