  This article is concerned with the rigorous validation of anomalous spreading
speeds in a system of coupled Fisher-KPP equations of cooperative type.
Anomalous spreading refers to a scenario wherein the coupling of two equations
leads to faster spreading speeds in one of the components. The existence of
these spreading speeds can be predicted from the linearization about the
unstable state. We prove that initial data consisting of compactly supported
perturbations of Heaviside step functions spreads asymptotically with the
anomalous speed. The proof makes use of a comparison principle and the explicit
construction of sub and super solutions.

Analysis of PDEs