2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/134964New exact solutions for the heat equation with a polynomial non-linearity and for the Fisher equation are found. An extended class of non-linear heat equations admitting solitary wave solutions is found. The generalization of the Fisher equation is proposed whose solutions propagate with arbitrary ad hoc fixed velocity.18 pages, LaTeX2eMathematical PhysicsAnalysis of PDEsExactly Solvable and Integrable Systems35K57; 35Q51; 58J70text