Relative weak compactness in infinite-dimensional Fefferman-Meyer duality

Fuente: arXiv
Gespeichert in:
Bibliographische Detailangaben
1. Verfasser: Melnikov, Vasily
Format: Preprint
Veröffentlicht: 2024
Schlagworte:
Online-Zugang:
Tags: Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
_version_ 1866929548690456576
author Melnikov, Vasily
author_facet Melnikov, Vasily
contents Let $E$ be a Banach space such that $E'$ has the Radon-Nikodým property. The aim of this work is to connect relative weak compactness in the $E$-valued martingale Hardy space $H^{1}(μ,E)$ to a convex compactness criterion in a weaker topology, such as the topology of uniform convergence on compacts in measure. These results represent a dynamic version of the deep result of Diestel, Ruess, and Schachermayer on relative weak compactness in $L^{1}(μ,E)$. In the reflexive case, we obtain a Kadec-Pełczyński dichotomy for $H^{1}(μ,E)$-bounded sequences, which decomposes a subsequence into a relatively weakly compact part, a pointwise weakly convexly convergent part, and a null part converging to zero uniformly on compacts in measure. As a corollary, we investigate a parameterized version of the vector-valued Komlós theorem without the assumption of $H^{1}(μ,E)$-boundedness.
format Preprint
id arxiv_https___arxiv_org_abs_2404_13416
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Relative weak compactness in infinite-dimensional Fefferman-Meyer duality
Melnikov, Vasily
Functional Analysis
Probability
46A50, 46E40, 60G44
Let $E$ be a Banach space such that $E'$ has the Radon-Nikodým property. The aim of this work is to connect relative weak compactness in the $E$-valued martingale Hardy space $H^{1}(μ,E)$ to a convex compactness criterion in a weaker topology, such as the topology of uniform convergence on compacts in measure. These results represent a dynamic version of the deep result of Diestel, Ruess, and Schachermayer on relative weak compactness in $L^{1}(μ,E)$. In the reflexive case, we obtain a Kadec-Pełczyński dichotomy for $H^{1}(μ,E)$-bounded sequences, which decomposes a subsequence into a relatively weakly compact part, a pointwise weakly convexly convergent part, and a null part converging to zero uniformly on compacts in measure. As a corollary, we investigate a parameterized version of the vector-valued Komlós theorem without the assumption of $H^{1}(μ,E)$-boundedness.
title Relative weak compactness in infinite-dimensional Fefferman-Meyer duality
topic Functional Analysis
Probability
46A50, 46E40, 60G44
url https://arxiv.org/abs/2404.13416