In this paper we present some results on the existence of /c-kernels and (k, [)-kernels in digraphs which generalize the following Theorem of P. Duchet [2]: "If every directed cycle of odd length in a digraph D has at least two symmetrical arcs, then D has a kernel.
(k,l)-kernels in line digraphs
β Scribed by Qin Lu; Er-fang Shan; Min Zhao
- Book ID
- 107482368
- Publisher
- Chinese Electronic Periodical Services
- Year
- 2006
- Tongue
- English
- Weight
- 244 KB
- Volume
- 10
- Category
- Article
- ISSN
- 1007-6417
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π SIMILAR VOLUMES
We define a fractional version of the notion of ``kernels'' in digraphs and prove that every clique acyclic digraph (i.e., one in which no clique contains a cycle) has a fractional kernel. Using this we give a short proof of a recent result of Boros and Gurvich (proving a conjecture of Berge and Duc
## Abstract A __quasiβkernel__ in a digraph is an independent set of vertices such that any vertex in the digraph can reach some vertex in the set via a directed path of length at most two. ChvΓ‘tal and LovΓ‘sz proved that every digraph has a quasiβkernel. Recently, Gutin et al. raised the question o
We call the digraph D an m-coloured digraph if the arcs of D are coloured with m colours. A directed path is called monochromatic if all of its arcs are coloured alike. A directed cycle is called quasi-monochromatic if with at most one exception all of its arcs are coloured alike. A set N C\_\_ V(D)