Angewandte Mathematik in USA

Angewandte Mathematik Und Informatik Universit at Zu K Oln

Institut für Numerische und Angewandte Mathematik Parallel Total Variation Minimization

In [ROF92] Rudin, Osher and Fatemi introduced a denoising algorithm using total variation regularization. In this work we provide a parallel algorithm for this variational minimization problem. It is based on the primal-dual formulation and hence leads to solve the saddle point problem for the primal and dual variable. For that reason Newton’s method with damping was used. The arising constrain...

Angewandte Mathematik Und Informatik Universit at Zu K Oln Onion Skins in Oriented Matroids

We generalize the following theorem to oriented matroids: Consider a polytope P and a facet F 0 of P, let H denote the hyperplanes spanned by F 0. Let d denote the diameter of the coskeleton of P. To each facet choose a deening inequality and let these set of inequalities F be partitioned by the distance of the corresponding facets to F 0 in the coskeleton of P into F = d

Angewandte Mathematik Und Informatik Universit at Zu K Oln Colouring Graphs with Prescribed Induced Cycle Lengths

In this paper we study the chromatic number for graphs with two prescribed induced cycle lengths. It is due to Sumner that triangle-free and P 5-free and triangle-free, P 6-free and C 6-free graphs are 3-colourable. A canonical extension of these graph classes is G

Angewandte Mathematik Und Informatik Universit at Zu K Oln Approximation of Geometric Dispersion Problems

We consider problems of distributing a number of points within a polygonal region P, such that the points are \far away" from each other. Problems of this type have been considered before for the case where the possible locations form a discrete set. Dispersion problems are closely related to packing problems. While Hochbaum and Maass (1985) have given a polynomial time approximation scheme for...