Henri Berestycki, l'cole des Hautes tudes en Sciences Sociales (EHESS) Paris
"The speed of propagation for reaction-diffusion equations in general domains"
This talk is concerned with reaction-diffusion equations with advection in unbounded general domains or with spatially inhomogeneous equations. The reaction term is of Fisher (or KPP) type. First, in the periodic framework, I will give results for the existence of pulsating traveling fronts - a notion extending that of traveling fronts. Then, I will derive a formula to obtain the minimal speed of traveling fronts. A related topic is that of "asymptotic speed of spreading" which I will describe along with several other notions of spreading speed. This allows one to define and discuss the speed of propagation in general domains. I will present some results analyzing the effect of various factors - advection, reaction, diffusion and geometry of domain - on the speed of propagation. I report here on joint works with Francois Hamel and Nikolai Nadirashvili.
WEDNESDAY, October 20, 2004
Refreshments at 4:00 in Wean 6220.