Symmetries and nonlinear self-adjointness for a generalized fisher equation

Abstract

In this work we study a generalization of the well known Fisher equation from the point of view of the theory of symmetry reductions in partial differential equations. We determine the class of these equations which are nonlinear self-adjoint. By using a general theorem on conservation laws proved by Nail Ibragimov we find conservation laws for some of these partial differential equations without classical Lagrangians.