DAM
2007
13 years 4 months ago
2007
DAM
2007
13 years 4 months ago
2007
Covering numbers of precompact symmetric convex subsets of Hilbert spaces are investigated. Lower bounds are derived for sets containing orthogonal subsets with norms of their ele...
DAM
2007
13 years 4 months ago
2007
For two given graphs F and H, the Ramsey number R(F, H) is the smallest positive integer p such that for every graph G on p vertices the following holds: either G contains F as a ...
DAM
2007
13 years 4 months ago
2007
The packing chromatic number χρ(G) of a graph G is the smallest integer k such that the vertex set of G can be partitioned into packings with pairwise different widths. Several...
DAM
2007
13 years 4 months ago
2007
In this paper, we extend known relationships between Cayley digraphs and their subgraphs and coset graphs with respect to subgroups to obtain a number of general results on homomo...
DAM
2007
13 years 4 months ago
2007
DAM
2007
13 years 4 months ago
2007
We prove that local complementation and vertex deletion, operations from which vertexminors are defined, can simulate edge contractions. As an application, we prove that the rank...
DAM
2007
13 years 4 months ago
2007
In this paper, we prove that the harmonious coloring problem is NP-complete for connected interval and permutation graphs. Given a simple graph G, a harmonious coloring of G is a ...
DAM
2007
13 years 4 months ago
2007
Given A := {a1, . . . , am} ⊂ Rd whose affine hull is Rd, we study the problems of computing an approximate rounding of the convex hull of A and an approximation to the minimum ...
DAM
2007
13 years 4 months ago
2007
We study a many-to-many generalisation of the well-known stable roommates problem in which each participant seeks to be matched with a number of others. We present a linear-time a...