Generalizations of theorems from the Theory of Functions
Text from introduction: "Practically all of the text books and lectures on the Theory of Functions of a Complex Variable treat only those functions which have a derivative in every point of some given region. This derivative must be independent of the direction in which the increment of the variable is taken. Functions which have this property are called analytic functions of a complex variable. In some cases these are called simply functions, the non analytic functions not being considered functions at all."