Francois Dunlop, Krzysztof Topolski
Cassie's Law and Concavity of Wall Tension with Respect to Disorder
(265K, postscript)

ABSTRACT.  For the semi-infinite Ising model with quenched boundary disorder, 
we prove concavity inequalities for the difference of wall tensions 
associated with the minus and plus phases. These inequalities generalize 
phenomenological equalities known as Cassie's law.