Structure of the cc's of level sets: inclusion tree

Property:$A=$cc$([u\geq \lambda])$, $B=$cc$([u\leq\mu])$, $A\cap B\neq\emptyset$
$\Rightarrow A\subseteq B$ or $B\subseteq A$

Summer School on Mathematical Problems in Image Processing, Trieste, Italy, September 4th-18th 2000