Acta mathematica scientia, Series B >
NORMAL STRUCTURE AND SOME GEOMETRIC PARAMETERS RELATED TO THE MODULUS OFU-CONVEXITY IN BANACH SPACES
Received date: 2009-02-05
Revised date: 2009-10-14
Online published: 2011-05-20
We present a short and simple proof of the recent result of Yang and Wang [12]. Stimulated by their idea, two geometric parameters
UaX(ε) and βX(ε), both related to Gao's modulus of U-convexity of a Banach space X, are introduced. Their properties and the relationships with normal structure are studied. Some existing results involving normal structure and fixed points for non-expansive mappings in Banach spaces are improved.
Key words： uniform normal structure; modulus of convexity; ultrapower
Ji Gao , Satit Saejung . NORMAL STRUCTURE AND SOME GEOMETRIC PARAMETERS RELATED TO THE MODULUS OFU-CONVEXITY IN BANACH SPACES[J]. Acta mathematica scientia, Series B, 2011 , 31(3) : 1035 -1040 . DOI: 10.1016/S0252-9602(11)60295-6
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