Abstract:
We give some criteria for Möbius property of a homeomorphism of domains in $\bar R^n$ which preserves fixed anharmonic ratio $\lambda\neq0,1,\infty$. For the case of even-dimensional space as well as for the case of real $\lambda$ the requirement of a map to be homeomorphism in the theorem can be replaced by injectivity and Borel measurability. For a homeomorphism which slightly changes fixed cross-ratio we get the upper estimates for it's coefficient of quasiconformality.
Keywords:anharmonic ratio, Möbius mapping, geometric criteria of Möbius property, quasiconformal mapping, coefficient of quasiconformality.