Geodesic
Estimation of a quadratic function and the $p$-Banach–Saks property
Algebra i analiz, Tome 18 (2006) no. 4, pp. 185-197 
E. M. Semenov; F. A. Sukochev. Estimation of a quadratic function and the $p$-Banach–Saks property. Algebra i analiz, Tome 18 (2006) no. 4, pp. 185-197. http://geodesic.mathdoc.fr/item/AA_2006_18_4_a6/
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     author = {E. M. Semenov and F. A. Sukochev},
     title = {Estimation of a quadratic function and the $p${-Banach{\textendash}Saks} property},
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     volume = {18},
     number = {4},
     language = {ru},
     url = {http://geodesic.mathdoc.fr/item/AA_2006_18_4_a6/}
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Voir la notice de l'article provenant de la source Math-Net.Ru

Let $E$ be a rearrangement-invariant Banach function space on $[0,1]$, and let $\Gamma(E)$ denote the set of all $p\ge 1$ such that any sequence $\{x_n\}$ in $E$ converging weakly to 0 has a subsequence $\{y_n\}$ with $\sup_m m^{-1/p}\|\sum_{1\le k\le m}y_n\|<\infty$. The set $\Gamma_i(E)$ is defined similarly, but only sequences $\{x_n\}$ of independent random variables are taken into account. It is proved (under the assumption $\Gamma(E)\ne\{1\}$) that if $\Gamma_i(E)\setminus\Gamma(E)\ne\varnothing$, then $\Gamma_i(E)\setminus\Gamma(E)=\{2\}$.

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