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The Generalisation of Tutte's Result for Chromatic Trees, by Lagrangian Methods

Published online by Cambridge University Press:  20 November 2018

D. M. Jackson
Affiliation:
University of Waterloo, Waterloo, Ontario
I. P. Goulden
Affiliation:
University of Waterloo, Waterloo, Ontario
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A K-coloured rooted tree t is said to have colour partitionL if L is a K × ∞ matrix with elements lij equal to the number of non-root vertices of colour i and degree j. If adjacent vertices are of different colours then t is called a chromatic tree and L a chromatic partition. The tree has edge partitionD where D is a K × K matrix with elements dij equal to the number of edges, directed away from the root, from a vertex of colour i to a vertex of colour j.

In this paper we consider a method for enumerating trees with respect to colour and degree information. The method makes use of elementary decompositions of trees, and the functional equations which are induced. A number of new results are obtained by this means. More specifically, we consider (Section 3) the enumeration of rooted plane X-coloured trees with given colour and edge partitions.

Type
Research Article
Copyright
Copyright © Canadian Mathematical Society 1981

References

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