Hopf differentials and smoothing Sobolev homeomorphisms
arXiv:1006.5174 · doi:10.1093/imrn/rnr144
Abstract
We prove that planar homeomorphisms can be approximated by diffeomorphisms in the Sobolev space and in the Royden algebra. As an application, we show that every discrete and open planar mapping with a holomorphic Hopf differential is harmonic.
22 pages, 0 figures