m at h . FA ] 1 2 A pr 1 99 4 IDEAL NORMS AND TRIGONOMETRIC ORTHONORMAL SYSTEMS
نویسنده
چکیده
Abstract. In this article, we characterize the UMD–property of a Banach space X by ideal norms associated with trigonometric orthonormal systems. The asymptotic behavior of that numerical parameters can be used to decide whether or not X is a UMD–space. Moreover, in the negative case, we obtain a measure that shows how far X is from being a UMD–space. The main result is, that all described parameters are equivalent also in the quantitative setting.
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تاریخ انتشار 1994