English

On the "Multiple of the Inclusion Plus Compact" Problem

Functional Analysis 2007-05-23 v1

Abstract

The ``multiple of the inclusion plus compact problem'' which was posed by T.W. Gowers in 1996 and Th. Schlumprecht in 2003, asks whether for every infinite dimensional Banach space XX there exists a closed subspace YY of XX and a bounded linear operator from YY to XX which is not a compact perturbation of a multiple of the inclusion map from YY to XX. We give sufficient conditions on the spreading models of seminormalized basic sequences of a Banach space XX which guarantee that the ``multiple of the inclusion plus compact'' problem has an affirmative answer for XX. Our results strengthen a previous result of the first named author, E.~Odell, Th. Schlumprecht and N. Tomczak-Jaegermann as well as a result of Th. Schlumprecht. We give an example of a Hereditarily Indecomposable Banach space where our results apply. For the proof of our main result we use an extension of E. Odell's Schreier unconditionality result for arrays.

Keywords

Cite

@article{arxiv.math/0701354,
  title  = {On the "Multiple of the Inclusion Plus Compact" Problem},
  author = {George Androulakis and Frank Sanacory},
  journal= {arXiv preprint arXiv:math/0701354},
  year   = {2007}
}