Robert Beauwens

TL;DR: The uptake of radioactive iodide or chloride by plasma membrane vesicles of bovine thyroid was studied by a rapid filtration technique and the data support the existence of two anionic channels.

TL;DR: This work shows that the preconditioned conjugate gradient method performs better than efficient direct methods for solving large sparse symmetric positive definite linear systems.

TL;DR: A remedy which consists in slightly moving the spectrum of the original system matrix along the imaginary axis is examined, which displays the efficiency of the new preconditioning techniques.

TL;DR: In this article, the authors obtained eigenvalue bounds for pencils of matrices A − vB where A is a Stieltjes matrix and B is positive definite, under assumptions suitable for the estimation of asymptotic convergence rates of factorization iterative methods.

TL;DR: In this paper, a nice perturbation technique was introduced by Axelsson and further developed by Gustafsson to prove that factorization iterative methods are able, under appropriate conditions, to reach a convergence rate larger by an order of magnitude than that of classical schemes.