57 citations · 252 across the 40 of their papers we have counts for
4 papers · 2 filters
The Nitsche conjecture
Tadeusz Iwaniec, Leonid V. Kovalev, Jani Onninen
The conjecture in question concerns the existence of a harmonic homeomorphism between circular annuli A(r,R) and A(r*,R*), and is motivated in part by the existence problem for dou…
An N-dimensional version of the Beurling-Ahlfors extension
Leonid V. Kovalev, Jani Onninen
We extend monotone quasiconformal mappings from dimension n to n+1 while preserving both monotonicity and quasiconformality. The extension is given explicitly by an integral operat…
Harmonic mappings of an annulus, Nitsche conjecture and its generalizations
Tadeusz Iwaniec, Leonid V. Kovalev, Jani Onninen
As long ago as 1962 Nitsche conjectured that a harmonic homeomorphism between planar annuli exists if and only if $\frac{R_*}{r_*} \ge {1/2} (\fra…
Variation of quasiconformal mappings on lines
Leonid V. Kovalev, Jani Onninen
We obtain improved regularity of homeomorphic solutions of the reduced Beltrami equation, as compared to the standard Beltrami equation. Such an improvement is not possible in term…