## Abstract Given a set __F__ of digraphs, we say a graph __G__ is a __F__β__graph__ (resp., __F__\*β__graph__) if it has an orientation (resp., acyclic orientation) that has no induced subdigraphs isomorphic to any of the digraphs in __F__. It is proved that all the classes of graphs mentioned in
Lexicographic orientation and representation algorithms for comparability graphs, proper circular arc graphs, and proper interval graphs
β Scribed by Pavon Hell; Jing Huang
- Publisher
- John Wiley and Sons
- Year
- 1995
- Tongue
- English
- Weight
- 823 KB
- Volume
- 20
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
Abstract
We introduce a simple new technique which allows us to solve several problems that can be formulated as seeking a suitable orientation of a given undirected graph. In particular, we use this technique to recognize and transitively orient comparability graphs, to recognize and represent proper circular arc graphs, and to recognize and represent proper interval graphs. As a consequence, we derive and represent proper interval graphs. As a consequence, we derive simple new proofs of a theorem of GhouilaβHouri and a theorem of Skrien. Our algorithms are conceptually simpler than (and often of comparable efficiency to) the existing algorithms for these problems. Β© 1995 John Wiley & Sons, Inc.
π SIMILAR VOLUMES
## Abstract We show that for an interval graph given in the form of a family of intervals, a maximum independent set, a minimum covering by disjoint completely connected sets or cliques, and a maximum clique can all be found in __O__(__n__ log __n__) time [__O__(__n__) time if the endpoints of the
## Abstract The __p__βcenter problem is to locate __p__ facilities on a network so as to minimize the largest distance from a demand point to its nearest facility. The __p__βmedian problem is to locate __p__ facilities on a network so as to minimize the average distance from a demand point to its c
Let G = (V, E) be a graph and let k be a nonnegative integer. A vector c β Z V + is called k-colorable iff there exists a coloring of G with k colors that assigns exactly c(v) colors to vertex v β V . Denote by Ο(G) and Ο f (G) the chromatic number and fractional chromatic number, respectively. We p