Lie group symmetries as integral transforms of fundamental solutions

We obtain fundamental solutions for PDEs of the form ut = σ xγ ux x + f (x) ux - μ xr u by showing that if the symmetry group of the PDE is nontrivial, it contains a standard integral transform of the fundamental solution. We show that in this case, the problem of finding a fundamental solution can be reduced to inverting a Laplace transform or some other classical transform. © 2006 Elsevier Inc. All rights reserved