Grossman and Ha ggkvist gave a sufficient condition under which a two-edgecoloured graph must have an alternating cycle (i.e., a cycle in which no two consecutive edges have the same colour). We extend their result to edge-coloured graphs with any number of colours. That is, we show that if there is
A note on coloured quadrangulations
β Scribed by Kenneth A. Berman
- Publisher
- Elsevier Science
- Year
- 1980
- Tongue
- English
- Weight
- 175 KB
- Volume
- 29
- Category
- Article
- ISSN
- 0012-365X
No coin nor oath required. For personal study only.
β¦ Synopsis
Consider a quadrilateral drawn in the plane labelled ABCD counter-clockwise. Partition this quadrilateral into smaller quadrilaterals by selecting an even number of points (or no points) on each of the sides and any number of points in the interior. The resultant map is a planar quadrungulation, that is ti planar map such that each face has valency 4 except possibly the outside face. (See [I]). Label the points on the side AB alternately A and B. Similarly label the points on the other three sides alternately B aod C, C and D, D and A. Now, label the interior points in any way such that no two adjacent points (perimeter or interior) have the same label. Call the resultant coloured quadrangulation Q. There are 24 possible labellings of the small quadrilaterals, six of which use all four labels. In Fig. 1, an example of a coloured quadrangulation Q is given. Note that there is a small quadrilateral labelled ABCD counterclockwise.
The purpose of this note is to prove the following theorem.
π SIMILAR VOLUMES
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