We prove that the graph isomorphism problem restricted to trees and to colored graphs with color multiplicities 2 and 3 is many-one complete for several complexity classes within NC 2 . In particular we show that tree isomorphism, when trees are encoded as strings, is NC 1 -hard under AC 0 -reductio
Some APX-completeness results for cubic graphs
β Scribed by Paola Alimonti; Viggo Kann
- Publisher
- Elsevier Science
- Year
- 2000
- Tongue
- English
- Weight
- 122 KB
- Volume
- 237
- Category
- Article
- ISSN
- 0304-3975
No coin nor oath required. For personal study only.
β¦ Synopsis
Four fundamental graph problems, Minimum vertex cover, Maximum independent set, Minimum dominating set and Maximum cut, are shown to be APX-complete even for cubic graphs. Therefore, unless P = NP, these problems do not admit any polynomial time approximation scheme on input graphs of degree bounded by three.
π SIMILAR VOLUMES
Shee, S.-C., Some results on I-valuation of graphs involving complete bipartite graphs, Discrete Mathematics 87 (1991) 73-80. In this paper we show that a graph G obtained from a complete bipartite graph K,,, and a collection of q (cmax{m, n}) stars G, by joining the centre of G, to every vertex of
## Abstract It is known that a necessary condition for the existence of a 1βrotational 2βfactorization of the complete graph __K__~2__n__+1~ under the action of a group __G__ of order 2__n__ is that the involutions of __G__ are pairwise conjugate. Is this condition also sufficient? The complete ans