Abstract
The generalized diffusion equations, with nonlinear source terms which encompasses the Fisher, Newell-Whitehead, FitzHugh-Nagumo and Allen-Cahn equations as particular forms are solved by the G'/G-expansion method. The exact solutions are in terms of hyperbolic, trigonometric and rational functions with external parameters. This paper concludes with the stationary topological soliton solution of the FitzHugh-Nagumo equation that is obtained by the Ansatz method. (C) 2010 The Franklin Institute. Published by Elsevier Ltd. All rights reserved.