Functions of a Complex Variable Functions of complex variables Difference and Functional Equations Functional equations Functions of real variables Mathematics Real Functions Special Functions Special functions Astronomy Astronomy, Astrophysics and Cosmology Astrophysics Difference equations Differential equations Functions, special Ordinary Differential Equations Sequences (Mathematics) Sequences, Series, Summability Λειτουργίες Συναρτήσεις, Ειδικές