We study the (I)-envelopes of the unit balls of Banach spaces. We show, in particular, that any nonreflexive space can be renormed in such a way that the (I)-envelope of the unit ball is not the whole bidual unit ball. Further, we give a simpler proof of James' characterization of reflexivity in the nonseparable case. We also study the spaces in which the (I)-envelope of the unit ball adds nothing.
@article{bwmeta1.element.bwnjournal-article-doi-10_4064-sm182-1-2, author = {Ond\v rej F. K. Kalenda}, title = {(I)-envelopes of unit balls and James' characterization of reflexivity}, journal = {Studia Mathematica}, volume = {178}, year = {2007}, pages = {29-40}, zbl = {1139.46018}, language = {en}, url = {http://dml.mathdoc.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm182-1-2} }
Ondřej F. K. Kalenda. (I)-envelopes of unit balls and James' characterization of reflexivity. Studia Mathematica, Tome 178 (2007) pp. 29-40. http://gdmltest.u-ga.fr/item/bwmeta1.element.bwnjournal-article-doi-10_4064-sm182-1-2/