Packing, wn*- separation and normal structure in Banach spaces
Ji Gao · Fixed Point Theory · 2020
Let X and X * be a Banach space and its dual, and let B(X) and S(X) be the unit ball and unit sphere of X respectively. In this paper, we introduce a new parameter of w * n -Separation, w * n (X * ), in X * and study the relation between this parameter and normal structure in X, and the relation between packing constant P (, X) introduced by Kottman and normal structure that implies the existence of fixed point for non-expansive mappings. Some new results about fixed points of non-expansive mapping are obtained.