| Contents |
| We propose a system to describe the influence of a "road" with fast diffusion on biological invasions. Outside of the road a classical Fisher-KPP propagation with a different diffusion takes place.
It is found that, if the ratio between the two diffusivities is above an explicit threshold, the road enhances the asymptotic speed of propagation in a cone of directions around the road. Outside this cone the speed of propagation coincides with the classical Fisher-KPP invasion speed. A description of the asymptotic shape of expansion is then derived. |
|