CHARACTERIZATIONS OF INNER PRODUCT SPACES BY INEQUALITIES INVOLVING SEMI-INNER PRODUCT

被引:0
|
作者
Wojcik, Pawel [1 ]
机构
[1] Pedag Univ Cracow, Inst Math, PL-30084 Krakow, Poland
来源
关键词
Semi-inner product; characterization of inner product spaces; inequality; projection; smoothness; norm derivative;
D O I
10.7153/mia-18-64
中图分类号
O1 [数学];
学科分类号
0701 ; 070101 ;
摘要
Using the notion of semi-inner product in normed spaces, in this paper we provide some new characterizations of inner product spaces. We answer a question posed by Dragomir, whether the property (N) is characteristic for inner product spaces. We show that the space X is of (N)-type if and only if the norm in X comes from an inner product.
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页码:879 / 885
页数:7
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