A note on a conjecture of Wintner and its disproof by Waldvogel
β Scribed by J. S. Griffith
- Publisher
- Springer Netherlands
- Year
- 1973
- Tongue
- English
- Weight
- 378 KB
- Volume
- 7
- Category
- Article
- ISSN
- 1572-9478
No coin nor oath required. For personal study only.
π SIMILAR VOLUMES
A graph H is a cover of a graph G, if there exists a mapping Ο from V (H) onto V (G) such that for every vertex v of G, Ο maps the neighbors of v in H bijectively onto the neighbors of Ο(v) in G. Negami conjectured in 1987 that a connected graph has a finite planar cover if and only if it embeds in
## Abstract In 1978 Woodall [6] conjectured the following: in a planar digraph the size of a shortest cycle is equal to the maximum cardinality of a collection of disjoint tranversals of cycles. We prove that this conjecture is true when the digraph is seriesβparallel. In fact, we prove a stronger