English

Geometry of reproducing kernels in model spaces near the boundary

Complex Variables 2015-10-01 v1

Abstract

We study two geometric properties of reproducing kernels in model spaces K_θK\_\thetawhere θ\theta is an inner function in the disc: overcompleteness and existence of uniformly minimalsystems of reproducing kernels which do not contain Riesz basic sequences. Both of these properties are related to the notion of the Ahern--Clark point. It is shown that "uniformly minimal non-Riesz" sequences of reproducing kernelsexist near each Ahern--Clark point which is not an analyticity point for θ\theta, whileovercompleteness may occur only near the Ahern--Clark points of infinite orderand is equivalent to a "zero localization property". In this context the notion ofquasi-analyticity appears naturally, and as a by-product of our results we give conditions in thespirit of Ahern--Clark for the restriction of a model space to a radius to be a class ofquasi-analyticity.

Keywords

Cite

@article{arxiv.1509.09077,
  title  = {Geometry of reproducing kernels in model spaces near the boundary},
  author = {Anton Baranov and Andreas Hartmann and Karim Kellay},
  journal= {arXiv preprint arXiv:1509.09077},
  year   = {2015}
}