Jian-Feng Zhu

On an Iwaniec--Kovalev--Onninen Conjecture for harmonic quasiconformal annulus mappings

In 2012, Iwaniec, Kovalev and Onninen proposed an upper Nitsche--Gr\"otzsch type estimate for harmonic $K$-quasiconformal homeomorphisms between circular annuli: in normalized form, every such map $h:A(1,s)\to A(1,S)$ should satisfy \[ S \leq \frac{K+1}{2}s-\frac{K-1}{2s}. \] The radial and spiral-radial one-mode model...