2014/09/07 by Benachour, Said, Iagar, Razvan Gabriel, Laurencot, Philippe
#Analysis of PDEs (math.AP) #FOS: Mathematics
paper · doi:10.48550/arxiv.1409.2154
We study the large time behavior of nonnegative solutions to the Cauchy problem for a fast diffusion equation with critical zero order absorption ∂tu-Δum+uq=0 \hboxin (0,∞)×\realN with mc:=(N-2)+/N < m < 1 and q=m+2/N. Given an initial condition u0 decaying arbitrarily fast at infinity, we show that the asymptotic behavior of the corresponding solution u is given by a Barenblatt profile with a logarithmic scaling, thereby extending a previous result requiring a specific algebraic lower bound on u0. A by-product of our analysis is the derivation of sharp gradient estimates and a universal lower bound, which have their own interest and hold true for general exponents q > 1.