  Known properties of Chebyshev polynomials are the following: they have simple
critical points with only two (finite) critical values. Those properties
uniquely determine the named polynomials modulo affine transformations of
dependent and independent variables. A similar property of Zolotarev fractions:
simple critical points and only four critical values generates already many
classes of rational functions modulo projective transformations of their
dependent and independent variables. They are listed in this note.

Complex Variables