English

Bi-Sobolev extensions

Complex Variables 2022-11-17 v1

Abstract

We give a full characterization of circle homeomorphisms which admit a homeomorphic extension to the unit disk with finite bi-Sobolev norm. As a special case, a bi-conformal variant of the famous Beurling-Ahlfors extension theorem is obtained. Furthermore we show that the existing extension techniques such as applying either the harmonic or the Beurling-Ahlfors operator work poorly in the degenerated setting. This also gives an affirmative answer to a question of Karafyllia and Ntalampekos.

Keywords

Cite

@article{arxiv.2211.08498,
  title  = {Bi-Sobolev extensions},
  author = {Aleksis Koski and Jani Onninen},
  journal= {arXiv preprint arXiv:2211.08498},
  year   = {2022}
}

Comments

18 pages, 2 figures

R2 v1 2026-06-28T05:59:23.646Z