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A geometric model of linear fractional transformations. (Russian. English summary) Zbl 1507.53012

Summary: A model of linear fractional transformations of the complex plane in the form of points of the complex three-dimensional projective space without a linear “forbidden” quadric is presented. A model of real linear fractional transformations of the complex plane in the form of points of the real three-dimensional projective space without a linear “forbidden” quadric is presented. A geometric separation of points corresponding to parabolic, hyperbolic and elliptic real linear fractional transformations by a “parabolic” cone touching the forbidden quadric is found. Some properties of model points corresponding to real linear fractional transformations are found. Some properties of model points corresponding to fundamental groups transformations of biconnected domains of the complex plane are found.

MSC:

53A20 Projective differential geometry
53C56 Other complex differential geometry