A Note on Harmonious Coloring of Caterpillars

Autor: Asahi Takaoka, Shingo Okuma, Satoshi Tayu, Shuichi Ueno
Rok vydání: 2015
Předmět:
Zdroj: IEICE Transactions on Information and Systems. :2199-2206
ISSN: 1745-1361
0916-8532
Popis: SUMMARY The harmonious coloring of an undirected simple graph is a vertex coloring such that adjacent vertices are assigned different colors and each pair of colors appears together on at most one edge. The harmonious chromatic number of a graph is the least number of colors used in such a coloring. The harmonious chromatic number of a path is known, whereas the problem to find the harmonious chromatic number is NP-hard even for trees with pathwidth at most 2. Hence, we consider the harmonious coloring of trees with pathwidth 1, which are also known as caterpillars. This paper shows the harmonious chromatic number of a caterpillar with at most one vertex of degree more than 2. We also show the upper bound of the harmonious chromatic number of a 3-regular caterpillar.
Databáze: OpenAIRE