Extinction properties of semilinear heat-equations with strong absorption

Abstract

Consider the initial-boundary value problem for ut=Δu-λu(q) with λ>0, 0<q<1; the initial data are nonnegative and the boundary data vanish. It is well known that the solution becomes extinct in finite time Τ, i.e., u(x, t) becomes identically zero for t ≥ T, where T is some positive number. In this paper we study the profile of x → u(x, t) as t → T.