Martin Barlow, University of British Columbia Richard F. Bass, University of Washington Krzysztof Burdzy, University of Washington
Abstract
Let $B$ be a Borel subset of $R^d$ and let $p(t,x,y)$ be the transition
densities of Brownian motion killed on leaving $B$. Fix $x$ and $y$
in $B$. If $p(t,x,y)$ is positive for one $t$, it is positive for
every value of $t$. Some related results are given.
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