关于λ-性质的讨论  

Two Open Problems About λ-property

作　　者：李刚[1] 马玉梅[2] 

机构地区：[1]河北广播电视大学教务处,河北石家庄050071 [2]河北师范大学数学与信息科学学院,河北石家庄050016

出　　处：《河北师范大学学报（自然科学版）》2000年第2期162-163,179,共3页Journal of Hebei Normal University：Natural Science

基　　金：国家博士点基金资助项目 !( 88513A)

摘　　要：:有些赋范空间的闭单位球具有称作“λ-性质”的几何特征 ,即闭单位球上的任一点 x均可表示为闭单位球端点 e和点 y(‖ y‖≤ 1)的凸组合 .举例说明了若 X有λ -性质 ,那么 l∞ ( X )和 X未必有λ -性质 ,从而证明 X和 l∞ ( X) ,X*There are many normed spaces,whose closed unit balls have the following geometric property,called λ property,in common,each member x of the unit ball is a convex combination,which is an extreme point e of the unit ball and a vector y ,where ‖ y ‖≤1 and e is assigned a positive weight.two open problems about λ property had been proved:though x has the λ property, l ∞(X) and X * then need not have the λ property.

关 键 词：Λ-性质 X^＊空间 赋范空间 闭单位球 几何特征 

分 类 号：O177.3[理学—数学]