Some Notes on Smoothness of Banach Spaces

Abstract:

      In this paper, We show that a real or complex Banach space is smooth at x₀(∈S(X)) iff, for any y∈S(X).(?)where X_x0,y= span {x₀, y} . For a real Banach space X, we obtain that X is F-differentia ble at x₀(∈S(X)) iff (?) Remark. The sufficient conditions of the conclusion have been proved by Yu Xintai [2].