Extending Greene's theorem to directed graphs
β Scribed by A.J Hoffman
- Publisher
- Elsevier Science
- Year
- 1983
- Tongue
- English
- Weight
- 213 KB
- Volume
- 34
- Category
- Article
- ISSN
- 0097-3165
No coin nor oath required. For personal study only.
π SIMILAR VOLUMES
## Abstract A semicycle is said to turn at a point __a__ if the arcs incident to __a__ are both to it or both from it. We prove that if a nonempty set of points of a finite directed graph contains a turning point of each semicycle, then one of its members is a turning point of every semicycle to wh
Siraii, J., Duke's theorem does not extend to signed graph embeddings, Discrete Mathematics, 94 (1991) 233-238. Using homology-type arguments and surface surgery it is proved that a direct extension of the classical Duke's contiguity theorem to cellular orientation embeddings of signed graphs is imp
In this note we point out a flaw in the separator theorem for rooted directed vertex graphs due to C. L. Monma and V. K. Wei (1986, J. Combin. Theory Ser. B 41, 141 181), and present a modified separator theorem for the same class of graphs.