Published online by Cambridge University Press: 10 December 2020
In this paper we consider the following problem: let Xk, be a Banach space with a normalised basis (e(k, j))j, whose biorthogonals are denoted by
${(e_{(k,j)}^*)_j}$
, for
$k\in\N$
, let
$Z=\ell^\infty(X_k:k\kin\N)$
be their l∞-sum, and let
$T:Z\to Z$
be a bounded linear operator with a large diagonal, i.e.,
Supported by the Austrian Science Foundation (FWF) under Grant Number Pr.Nr. P28352, P32728 and by the 2019 workshop in Analysis and Probability at Texas A&M University.
Supported by the National Science Foundation under Grant Number DMS-1912897.
Supported by the Austrian Science Foundation (FWF) under Grant Number Pr.Nr. P28352 and by the 2019 workshop in Analysis and Probability at Texas A&M University.
Supported by the National Science Foundation under Grant Numbers DMS-1464713 and DMS-1711076.