We prove that strictly elliptic operators with generalized Wentzell boundary conditions generate analytic semigroups of angle π /2 on the space of continuous function on a compact manifold with boundary. n i=1 x i y i . Moreover we denote by ֒→ a continuous and by c ֒→ a compact embedding.
The abstract settingAs in [EF05, Section 2] the basis of our investigation is the following Abstract Setting 2.1. Consider (i) two Banach spaces X and ∂X, called state and boundary space, respectively; (ii) a densely defined maximal operator A m : D(A m ) ⊂ X → X;