A Characterization Of U-Ideals In Reflexive Banach Spaces

ABSTRACT

In this thesis we show the retlexivity of a Banach space, that is spaces embedded in their

biduals.The concept is realized for the case that the canonical embedding into its bidual

is surjective.We characterize u-ideals in Banach spaces having retlexive properties. We

show that u-ideal achieves its norm on closed unit ball and for any retlexive Banach

space X; u-ideal is always a closed ideal. We also show that u-deal contained in

Jacobsonradical is a zero ring.