Banach空间中的Zbǎganu常数

The Zbǎganu constant of Banach space

研究Banach空间中的Zbǎganu常数在不动点中的一些应用。首先,分别讨论Zbǎganu常数与弱正交系数ω(X),系数R(X)的关系,得到了Banach空间满足DL条件的充分条件,从而得到Banach空间上的单值非扩张映射存在不动点。其次,讨论Zbǎganu常数与弱正交系数ω(X),系数R(X)和WCS(X)的一些关系。最后,利用凸系数ε0(X)与Zbǎganu常数的关系给出Banach空间X及对偶空间具有正规结构的充分条件。

Some applications in fixed point with the Zb^iganu constant of Banach space are studied. First, Some suf- ficient conditions for a Banach space has DL conditions by the generalization of Zbaganu constant with the coefficient of weak orthogonality ω （X） , coefficient R （X） , which imply the existence of fixed point for the single valued nonexpansive mappings. Second, the generalization of Zbaganu constant, the coefficient of weak orthogonality to （X） , coefficient R（X） and WCS（X） are investigated. Finally, some sufficient conditions with convex coefficient ε0 （X） and Zbaganu constant which imply a Banach space X and the dual space has normal structure are presented.