English

Explicit bounds for separation between Oseledets subspaces

Dynamical Systems 2018-08-23 v1

Abstract

We consider a two-sided sequence of bounded operators in a Banach space which are not necessarily injective and satisfy two properties (SVG) and (FI). The singular value gap (SVG) property says that two successive singular values of the cocycle at some index dd admit a uniform exponential gap; the fast invertibility (FI) property says that the cocycle is uniformly invertible on the fastest dd-dimensional direction. We prove the existence of a uniform equivariant splitting of the Banach space into a fast space of dimension dd and a slow space of co-dimension dd. We compute an explicit constant lower bound on the angle between these two spaces using solely the constants defining the properties (SVG) and (FI). We extend the results obtained in the finite-dimensional case for bijective operators and the results obtained by Blumenthal and Morris in the infinite-dimensional case for injective norm-continuous cocycles, in the direction that the operators are not required to be globally injective, that no dynamical system is involved, and no compactness of the underlying system or smoothness of the cocycle is required. Moreover, we give quantitative estimates of the angle between the fast and slow spaces that are new even in the case of finite-dimensional bijective operators in Hilbert spaces.

Keywords

Cite

@article{arxiv.1808.07230,
  title  = {Explicit bounds for separation between Oseledets subspaces},
  author = {Anthony Quas and Philippe Thieullen and Mohamed Zarrabi},
  journal= {arXiv preprint arXiv:1808.07230},
  year   = {2018}
}
R2 v1 2026-06-23T03:40:25.330Z