On the -theory for second-order elliptic operators in divergence form with complex coefficients
arXiv:1903.06692
Abstract
Given a complex, elliptic coefficient function we investigate for which values of the corresponding second-order divergence form operator, complemented with Dirichlet, Neumann or mixed boundary conditions, generates a strongly continuous semigroup on . Additional properties like analyticity of the semigroup, -calculus and maximal regularity are also discussed. Finally we prove a perturbation result for real coefficients that gives the whole range of 's for small imaginary parts of the coefficients. Our results are based on the recent notion of -ellipticity, reverse Hölder inequalities and Gaussian estimates for the real coefficients.
37 pages