A Variational Principle for the Asymptotic Speed of Fronts of the Density Dependent Diffusion--Reaction Equation

R. D. Benguria, M. C. Depassier

We show that the minimal speed for the existence of monotonic fronts of the equation $u_t=(u^m{)}_{xx}+f(u)$ with $f(0)=f(1)=0$, $m>1$ and $f>0$ in $(0,1)$ derives from a va…