## Abstract Bounds on the sum and product of the chromatic numbers of __n__ factors of a complete graph of order __p__ are shown to exist. The wellβknown theorem of Nordhaus and Gaddum solves the problem for __n__ = 2. Strict lower and some upper bounds for any __n__ and strict upper bounds for __n
Chromatic factorizations of a graph
β Scribed by S. Louis Hakimi; Edward F. Schmeichel
- Publisher
- John Wiley and Sons
- Year
- 1988
- Tongue
- English
- Weight
- 243 KB
- Volume
- 12
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
Let n, 2 n2 L . . B n, 2 2 be integers. We say that G has an (n,, n2, , . , , n,)-chromatic factorization if G can be edge-factored as G, @ G2 @ + . . @ G, with x ( G , ) = n,, for i = 1,2, . . . , k . The following results are proved : then K,, has an (n,, n2,, . , , n,)-chromatic factorization.
We consider only finite, undirected graphs without loops or multiple edges. Our notation and terminology will be standard except as indicated; a good reference for undefined terms is [ 11.
* U Ek be a partition of E ( G ) . De-
π SIMILAR VOLUMES
It was proved (A. Kotlov and L. LovΓ‘sz, The rank and size of graphs, J. Graph Theory 23 (1996), 185-189) that the number of vertices in a twin-free graph is O(( β 2) r ) where r is the rank of the adjacency matrix. This bound was shown to be tight. We show that the chromatic number of a graph is o(β
## Abstract We study a generalization of the notion of the chromatic number of a graph in which the colors assigned to adjacent vertices are required to be, in a certain sense, far apart. Β© 1993 John Wiley & Sons, Inc.
Following [1] , we investigate the problem of covering a graph G with induced subgraphs G 1 ; . . . ; G k of possibly smaller chromatic number, but such that for every vertex u of G, the sum of reciprocals of the chromatic numbers of the G i 's containing u is at least 1. The existence of such ''ch
A graph G is called triangulated (or rigid-circuit graph, or chordal graph) if every circuit of G with length greater than 3 has a chord. It can be shown (see, UI, . . . , u,, . Let G = G,.