English

Operator machines on directed graphs

Functional Analysis 2022-06-14 v1

Abstract

We show that if an infinite-dimensional Banach space X has a symmetric basis then there exists a bounded, linear operator R : X --> X such that the set A = {x in X : ||R^n(x)|| --> infinity} is non-empty and nowhere dense in X. Moreover, if x in X\A then some subsequence of (R^n(x)) converges weakly to x. This answers in the negative a recent conjecture of Prajitura. The result can be extended to any Banach space containing an infinite-dimensional, complemented subspace with a symmetric basis; in particular, all 'classical' Banach spaces admit such an operator.

Keywords

Cite

@article{arxiv.0906.0160,
  title  = {Operator machines on directed graphs},
  author = {Petr Hajek and Richard J. Smith},
  journal= {arXiv preprint arXiv:0906.0160},
  year   = {2022}
}
R2 v1 2026-06-21T13:08:05.785Z