Michael Karkulik

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Optimized Imex Runge-Kutta methods for simulations in astrophysics: A detailed study 13/2012 H. Woracek Asymptotics of eigenvalues for a class of singular Krein strings 12/2012 Quasi-optimal a priori estimates for fluxes in mixed finite element methods and applications to the Stokes-Darcy coupling Abstract. We prove convergence and quasi-optimality of a(More)
Inverse estimates for elliptic integral operators and application to the adaptive coupling of FEM and BEM 06/2012 Quasi-optimal a priori estimates for fluxes in mixed finite element methods and applications to the Stokes-Darcy coupling 04/2012 M. Langer, H. Woracek Indefinite Hamiltonian systems whose Titchmarsh-Weyl coefficients have no finite generalized(More)
We report on the Matlab program package HILBERT. It provides an easily-accessible implementation of lowest order adaptive Galerkin boundary element methods for the numerical solution of the Poisson equation in 2D. The library was designed to serve several purposes: The stable implementation of the integral operators may be used in research code. The(More)
On optimal L 2-and surface ux convergence in FEM (extended version) Abstract. We prove local inverse-type estimates for the four non-local boundary integral operators associated with the Laplace operator on a bounded Lipschitz domain Ω in R d for d ≥ 2 with piecewise smooth boundary. For piecewise polynomial ansatz spaces and d ∈ {2, 3}, the inverse(More)