RANDOMIZED SERIES AND GEOMETRY OF BANACH SPACES

Abstract

We study some properties of the randomized series and their applications to the geometric structure of Banach spaces. For $n \geq 2$ and $1 \lt p \lt \infty$, it is shown that $\ell^n_{\infty}$ is representable in a Banach space $X$ if and only if it is representable in the Lebesgue-Bochner $L_p(X)$. New criteria for various convexity properties in Banach spaces are also studied. It is proved that a Banach lattice $E$ is uniformly monotone if and only if its $p$-convexification $E^{(p)}$ is uniformly convex and that a Köthe function space $E$ is upper locally uniformly monotone if and only if its $p$-convexification $E^{(p)}$ is midpoint locally uniformly convex.