Wavefront's stability with asymptotic phase in the delayed monostable equations

Abstract

We extend the class of initial conditions for scalar delayed reaction-diffusion equations $u_t (t,x)=u_{xx}(t,x)+f(u(t, x), u(t-h, x))$ which evolve in solutions converging to monostable traveling waves. Our approach allows to compute, in the moving reference frame, the phase distortion $\alpha$ of the limiting travelling wave with respect to the position of solution at the initial moment $t=0$. In general, $\alpha\not=0$ for the Mackey-Glass type diffusive equation. Nevertheless, $\alpha=0$ for the KPP-Fisher delayed equation: the related theorem also improves existing stability conditions for this model.