Glasnik Matematicki, Vol. 39, No.2 (2004), 273--286.

ESTIMATES ON THE DIRICHLET HEAT KERNAL OF DOMAINS ABOVE THE GRAPHS OF BOUNDED C1,1 FUNCTIONS

Renming Song

Department of Mathematics, University of Illinois, Urbana, IL 61801, USA
e-mail: rsong@math.uiuc.edu


Abstract.   Suppose that D is the domain in Rd, d ≥ 3, above the graph of a bounded C1,1 function Γ : Rd-1 → R and that pD(t, x, y) is the Dirichlet heat kernel in D. In this paper we show that there exist positive constants C1, C2, C3, C4 such that for all t > 0 and x, y ∈ D,

C1(ρ(x)ρ(y) / t ∧ 1) t -d/2 e -C2|x-y|^2 / t ≤ pD(t, x, y),

pD(t, x, y) ≤ C3(ρ(x)ρ(y) / t ∧ 1) t -d/2 e -C4|x-y|^2 / t,

where ρ(x) stands for the distance between x and ∂D.

2000 Mathematics Subject Classification.   35K05, 60J60, 60J45, 60J75.

Key words and phrases.   Dirichlet heat kernels, Green functions, killed Brownian motions.


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