## Abstract We represent a graph by assigning each vertex a finite set such that vertices are adjacent if and only if the corresponding sets have at least two common elements. The __2βintersection number__ ΞΈ~2~(__G__) of a graph __G__ is the minimum size of the union of sets in such a representatio
The achromatic number of bounded degree trees
β Scribed by Niall Cairnie; Keith Edwards
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 621 KB
- Volume
- 188
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
The achromatic number ~b(G) of a simple graph G is the largest number of colours possible in a proper vertex colouring of G in which each pair of coiours appears on at least one edge.
The problem of determining the achromatic number of a tree is known to be NP-hard (Cairnie and Edwards, 1997). In this paper, we present a polynomial-time algorithm for determining the achromatic number of a tree with maximum degree at most d, where d is a fixed positive integer.
Prior to giving this algorithm, we show that there is a natural number N(d) such that if T is any tree with m>~N(d) edges, and maximum degree at most d, then ~(T) is k or k -1, where k is the largest integer such that (k2)~<m. (~
π SIMILAR VOLUMES
## Abstract The number of independent vertex subsets is a graph parameter that is, apart from its purely mathematical importance, of interest in mathematical chemistry. In particular, the problem of maximizing or minimizing the number of independent vertex subsets within a given class of graphs has
The achromatic number of a finite graph G, (G), is the maximum number of independent sets into which the vertex set may be partitioned, so that between any two parts there is at least one edge. For an m-dimensional hypercube P m 2 we prove that there exist constants 0<c 1 <c 2 , independent of m, su