English

Conformality of quasiconformal mappings at a point, revisited

Complex Variables 2018-05-01 v2

Abstract

We present a new and simple proof of Teichm\"uller-Wittich-Belinskii's and Gutlyanskii-Martio's theorems on the conformality of quasiconformal mappings at a given point. Known proofs gave separate estimates for the radial and angular variations, but our proof unifies them using Gr\"otzsch-type inequality for the variation of cross-ratio of four points on the Riemann sphere. We also give a sufficient condition for C1+αC^{1+\alpha}-conformality

Keywords

Cite

@article{arxiv.1802.09137,
  title  = {Conformality of quasiconformal mappings at a point, revisited},
  author = {Mitsuhiro Shishikura},
  journal= {arXiv preprint arXiv:1802.09137},
  year   = {2018}
}