MEASUREMENT OF THE DIFFERENCE OF TWO TYPES ORTHOGONALITY IN RADON PLANES (Nonlinear Analysis and Convex Analysis)

Abstract

The notion of orthogonality for vectors in inner product spaces is simple, interesting and fruitful. When moving to normed spaces, we have many possibilities to extend this notion. Recently the constants which measure the difference between these orthogonalities have been investigated. The usual orthognality in inner product spaces is symmetric. However, Birkhoff orthogonality in normed spaces is not symmetric in general. The norm plane in which Birkhoff orthogonality is symmetric is called a Radon plane. We consider the difference between Birkhoff and isosceles orthogonalities in Radon planes.