Article
Keywords:
Friedrichs' constant; a posteriori error estimates; eigenvalue problem
Summary:
This contribution presents a general numerical method for computing lower and
upper bound of the optimal constant in Friedrichs’ inequality. The standard Rayleigh-Ritz method is used for the lower bound and the method of $\textit {a\ priori-a\ posteriori\ inequalities}$ is employed for the upper bound. Several numerical experiments show applicability and accuracy of this approach.