Robust and Local Optimal A Priori Error Estimates for Interface Problems with Low Regularity: Mixed Finite Element Approximations
Provides theoretical error bounds for mixed finite element methods on interface problems, which is important for numerical analysts working on adaptive algorithms.
This paper establishes robust and locally optimal a priori error estimates for mixed finite element approximations of elliptic interface problems with low regularity, providing guidance for adaptive methods.
For elliptic interface problems in two- and three-dimensions with a possible very low regularity, this paper establishes a priori error estimates for the Raviart-Thomas and Brezzi-Douglas-Marini mixed finite element approximations. These estimates are robust with respect to the diffusion coefficient and optimal with respect to the local regularity of the solution. Several versions of the robust best approximations of the flux and the potential approximations are obtained. These robust and local optimal a priori estimates provide guidance for constructing robust a posteriori error estimates and adaptive methods for the mixed approximations.