Isomorphic spectrum and isomorphic length of a Banach space

We prove that, given any ordinal $\delta < \omega_2$, there exists a transfinite $\delta$-sequence of separable Banach spaces $(X_\alpha)_{\alpha < \delta}$ such that $X_\alpha$ embeds isomorphically into $X_\beta$ and contains no subspace isomorphic to $X_\beta$ for all $\alpha < \beta <...

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Bibliographic Details
Main Authors: O. Fotiy, M. Ostrovskii, M. Popov
Format: Article
Language:English
Published: Vasyl Stefanyk Precarpathian National University 2020-06-01
Series:Karpatsʹkì Matematičnì Publìkacìï
Subjects:
Online Access:https://journals.pnu.edu.ua/index.php/cmp/article/view/3879
Description
Summary:We prove that, given any ordinal $\delta < \omega_2$, there exists a transfinite $\delta$-sequence of separable Banach spaces $(X_\alpha)_{\alpha < \delta}$ such that $X_\alpha$ embeds isomorphically into $X_\beta$ and contains no subspace isomorphic to $X_\beta$ for all $\alpha < \beta < \delta$. All these spaces are subspaces of the Banach space $E_p = \bigl( \bigoplus_{n=1}^\infty \ell_p \bigr)_2$, where $1 \leq p < 2$. Moreover, assuming Martin's axiom, we prove the same for all ordinals $\delta$ of continuum cardinality.
ISSN:2075-9827
2313-0210