In this chapter we start from two fundamental memoirs of Gauss and Beltrami on complex variables on surfaces described by a definite quadratic form. By using the functions of a hyperbolic variable, we extend the results of the classic authors to surfaces in space-times described by non-definite quadratic forms. © 2008 Birkhäuser Verlag AG.
All Science Journal Classification (ASJC) codes
- Mathematics (miscellaneous)