The Analysis of a Nested Dissection Algorithm.
It is well-known that the idea of transferring boundary conditions offers a universal and, in addition, elementary means how to investigate almost all methods for solving boundary value problems for ordinary differential equations. The aim of this paper is to show that the same approach works also for discrete problems, i.e., for difference equations. Moreover, it will be found out that some results of this kind may be obtained also for some particular two-dimensional problems.
In der Arbeit wird in gewisses mehrparametriges Iterationsverfahren für die Lösung spezieller linearer Gleichungssysteme untersucht. Es handlet sich um Gleichungssysteme mit einer Matrix, die eine grosse Anzahl von Nullelementen enthält. Bei der Auswahl der Parameter wird die spezielle Struktur der Matrix ausgenützt. Es werden auch Fragen der Konvergenzgeschwindigkeit des untersuchten Verfahrens behandelt.
For a class of anisotropic integrodifferential operators arising as semigroup generators of Markov processes, we present a sparse tensor product wavelet compression scheme for the Galerkin finite element discretization of the corresponding integrodifferential equations u = f on [0,1]n with possibly large n. Under certain conditions on , the scheme is of essentially optimal and dimension independent complexity (h-1| log h |2(n-1)) without corrupting the convergence or smoothness requirements...