  We study the Laplace operator on the Sierpinski gasket with nonlinear Robin
boundary conditions. We show that for certain Robin boundary conditions the
Laplace operator generates a positive, order preserving, $L^\infty$-contractive
semigroup which is sandwiched (in the sense of domination) between the
semigroups generated by the Dirichlet-Laplace operator and the Neumann-Laplace
operator. We also characterise all local semigroups which are sandwiched
between these two extremal semigroups by showing that their generators are
Robin-Laplace operators.
