Gradient estimates, Harnack inequalities and estimates for heat kernels of the sum of squares of vector fields


Yen-Wen Fan

15:30:00 - 17:00:00

R202 , Astronomy and Mathematics Building

In this talk we will review the paper by H.-D. Cao and S.-T. Yau in Math. Z. (1992). This is an analogue of gradient estimate for the parabolic equation. In our case the operator is degenerate and if we assume that [Xi,[ Xj, Xk]] can be expressed as linear combinations of Xi and their brackets, then we have analogous gradient estimate for the sum of square parabolic type equation.