The Quarterly Journal of Mathematics Advance Access published online on January 2, 2009
The Quarterly Journal of Mathematics, doi:10.1093/qmath/han036
ASYMPTOTIC UNCONDITIONALITY


Department of Mathematics, University of Missouri-Columbia, Columbia, MO 65211, USA
Corresponding author. E-mail: nigel{at}math.missouri.edu
Received 16 September 2008;
| Abstract |
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We show that a separable real Banach space embeds almost isometrically in a space Y with a shrinking 1-unconditional basis if and only if lim n
|| x* + xn*|| = lim n
||x* – xn*|| whenever x*
X*,
is a weak*-null sequence and both limits exist. If X is reflexive then Y can be assumed reflexive. These results provide the isometric counterparts of recent work of Johnson and Zheng.
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