Let G be a planar graph. The vertex face total chromatic number ,y13(G) of G is the least number of colors assigned to V(G) U F(G) such that no adjacent or incident elements receive the same color. The main results of this paper are as follows: (1) We give the vertex face total chromatic number for
On the face touching number
β Scribed by Sanders, Daniel P.
- Publisher
- John Wiley and Sons
- Year
- 1996
- Tongue
- English
- Weight
- 399 KB
- Volume
- 23
- Category
- Article
- ISSN
- 0364-9024
No coin nor oath required. For personal study only.
β¦ Synopsis
In a 3-connected plane graph, each pair of faces meet at at most either a vertex or an edge. Zha considered 3-connected graphs embedded on the projective plane, torus, and Klein bottle, showing that they meet at at most two, at most four, and a t most four vertices or edges, respectively, and demonstrated graphs that showed that these bounds were best possible. He asked the question on what the maximum number of times two faces can meet on a general surface. This paper solves that problem, showing that two faces of a graph embedded on a non-planar surface of Euler characteristic E meet at most 4 -2 ~ times. The proof uses the Discharging Method, and seems to be the first application of this method to a problem which is wholly about graph embeddings. Also, graphs are demonstrated to show that this result is best possible.
π SIMILAR VOLUMES
In this paper, we shall first prove that for a Halin graph G, 4 Β°xT (G) Β°6, where x T (G) is the vertex-face total chromatic number of G. Second, we shall establish a sufficient condition for a Halin graph to have a vertex-face total chromatic number of 6. Finally, we shall give a necessary and suff
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