Owen M.P.
A Riemannian Off-Diagonal Heat Kernel Bound for Uniformly Elliptic Operators
(661K, Postscript)

ABSTRACT.  We find a Gaussian off-diagonal heat kernel estimate for uniformly
elliptic operators with measurable coefficients acting on regions $\Omega 
\subseteq\real^N$, where the order $2m$ of the operator satisfies $N<2m$. 
The estimate is expressed using certain Riemannian-type metrics, and a 
geometrical result is established allowing conversion of the estimate into 
terms of the usual Riemannian metric on $\Omega$. Work of Barbatis is 
applied to find the best constant in this expression.