Strong chromatic index of subset graphs
β Scribed by Quinn, Jennifer J.; Benjamin, Arthur T.
- Publisher
- John Wiley and Sons
- Year
- 1997
- Tongue
- English
- Weight
- 115 KB
- Volume
- 24
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
The strong chromatic index of a graph G, denoted sq(G), is the minimum number of parts needed to partition the edges of G into induced matchings. For 0 β€ k β€ l β€ m, the subset graph S m (k, l) is a bipartite graph whose vertices are the kand l-subsets of an m element ground set where two vertices are adjacent if and only if one subset is contained in the other. We show that sq(S m (k, l)) = ( m l-k ) and that this number satisfies the strong chromatic index conjecture by Brualdi and Quinn for bipartite graphs. Further, we demonstrate that the conjecture is also valid for a more general family of bipartite graphs.
π SIMILAR VOLUMES
A k-critical (multi-) graph G has maximum degree k, chromatic index Ο (G) = k + 1, and Ο (G -e) < k + 1 for each edge e of G. For each k β₯ 3, we construct k-critical (multi-) graphs with certain properties to obtain counterexamples to some well-known conjectures.
We show that coloring the edges of a multigraph G in a particular order often leads to improved upper bounds for the chromatic index Ο (G). Applying this to simple graphs, we significantly generalize recent conditions based on the core of G (i.e., the subgraph of G induced by the vertices of degree
We introduce in this paper the notion of the chromatic number of an oriented graph G (that is of an antisymmetric directed graph) defined as the minimum order of an oriented graph H such that G admits a homomorphism to H. We study the chromatic number of oriented k-trees and of oriented graphs with
This note proves that the game chromatic number of an outerplanar graph is at most 7. This improves the previous known upper bound of the game chromatic number of outerplanar graphs.