On strong orthogonality and strictly convex normed linear spaces
Kallol Paul, Debmalya Sain, Kanhaıya Jha · Journal of Inequalities and Applications · 2013
Abstract We introduce the notion of a strongly orthogonal set relative to an element in the sense of Birkhoff-James in a normed linear space to find a necessary and sufficient condition for an element x of the unit sphere S X to be an exposed point of the unit ball B X . We then prove that a normed linear space is strictly convex iff for each element x of the unit sphere, there exists a bounded linear operator A on X which attains its norm only at the points of the form λx with λ ∈ S K . MSC:46B20, 47A30.