2010/09/03 by Ma, Li
#Differential Geometry (math.DG) #FOS: Mathematics
paper · doi:10.48550/arxiv.1009.0603
In this paper, we study the gradient estimates of Li-Yau-Hamilton type for positive solutions to both drifting heat equation and the simple nonlinear heat equation problem ut-Δu=aulog u, ugt;0 on the compact Riemannian manifold (M,g) of dimension n and with non-negative (Bakry-Emery)-Ricci curvature. Here a≤ 0 is a constant. The latter heat equation is a basic evolution equation which is the negative gradient heat flow to the functional of Log-Sobolev inequality on the Riemannian manifold. We derive various versions of gradient estimates which generalize Hamilton's gradient estimate. An question concerning the Hamilton type gradient estimate for the simple nonlinear heat equation is addressed.