ALGORITHMICA
2011
12 years 11 months ago
2011
We show that computing the crossing number and the odd crossing number of a graph with a given rotation system is NP-complete. As a consequence we can show that many of the well-k...
WG
2010
Springer
13 years 2 months ago
2010
Springer
The vertex colouring problem is known to be NP-complete in the class of triangle-free graphs. Moreover, it remains NP-complete even if we additionally exclude a graph F which is n...
LATIN
2010
Springer
13 years 2 months ago
2010
Springer
Abstract In this paper, we settle the open complexity status of interval constrained coloring with a fixed number of colors. We prove that the problem is already NP-complete if th...
IPL
2008
13 years 4 months ago
2008
We show that deciding if a mixed graph has a well-balanced orientation is NP-complete.
DAM
2008
13 years 4 months ago
2008
We study a variant of the pickup-and-delivery problem (PDP) in which the objects that have to be transported can be reloaded at most d times, for a given d N. This problem is kno...
DAM
2008
13 years 4 months ago
2008
We define a new set of functions called semi-monotone, a subclass of skew-supermodular functions. We show that the problem of augmenting a given graph to cover a symmetric semi-mo...
CORR
2010
Springer
13 years 4 months ago
2010
Springer
Deciding whether a graph can be embedded in a grid using only unitlength edges is NP-complete, even when restricted to binary trees. However, it is not difficult to devise a numbe...