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The achromatic number of bounded degree trees

✍ Scribed by Niall Cairnie; Keith Edwards


Publisher
Elsevier Science
Year
1998
Tongue
English
Weight
621 KB
Volume
188
Category
Article
ISSN
0012-365X

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✦ 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. (~


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