Abstract
O. Kobayashi [6] in 2007 proved that $C^1$-mappings preserving anharmonic ratio are Moebius transformations. We strengthen his theorem and prove that the requirement of differentiability and even of injectivity can be omitted.
Citation
Kergylova TATYANA. Aseev VLADISLAV. "On Transformations that Preserve Fixed Anharmonic Ratio." Tokyo J. Math. 33 (2) 365 - 371, December 2010. https://doi.org/10.3836/tjm/1296483476
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