On the geometry of projective tensor products

Autor: Nicole Tomczak-Jaegermann, Carsten Schütt, Elisabeth M. Werner, Joscha Prochno, Ohad Giladi
Rok vydání: 2017
Předmět:
Zdroj: Journal of Functional Analysis. 273:471-495
ISSN: 0022-1236
DOI: 10.1016/j.jfa.2017.03.019
Popis: In this work, we study the volume ratio of the projective tensor products $\ell^n_p\otimes_{\pi}\ell_q^n\otimes_{\pi}\ell_r^n$ with $1\leq p\leq q \leq r \leq \infty$. We obtain asymptotic formulas that are sharp in almost all cases. As a consequence of our estimates, these spaces allow for a nearly Euclidean decomposition of Kashin type whenever $1\leq p \leq q\leq r \leq 2$ or $1\leq p \leq 2 \leq r \leq \infty$ and $q=2$. Also, from the Bourgain-Milman bound on the volume ratio of Banach spaces in terms of their cotype $2$ constant, we obtain information on the cotype of these $3$-fold projective tensor products. Our results naturally generalize to $k$-fold products $\ell_{p_1}^n\otimes_{\pi}\dots \otimes_{\pi}\ell_{p_k}^n$ with $k\in\mathbb N$ and $1\leq p_1 \leq \dots\leq p_k \leq \infty$.
Comment: 21 pages
Databáze: OpenAIRE