Generalization of Exp-function and other standard function methods

Exp-function and other standard function methods for solving nonlinear differential equations are generalized in this paper. An analytical criterion determining if a solution can be expressed in a form comprising standard functions is derived. New computational algorithm for automatic identification of the structure of the solution is constructed. The algorithm provides information if the solution can be expressed as a sum of standard functions, a ratio of sums of standard functions, or even a more complex algebraic form involving standard functions. Several examples are used to illustrate the proposed concept.