Abstract
Kernel is an important topic in digraphs. A digraph such that every proper induced subdigraph has a kernel is said to be critical kernel imperfect (CKI, for short) if the digraph does not have a kernel. Galeana-Sánchez and Olsen characterized the CKI-digraphs for the following families of digraphs: asymmetric arc-locally in-/out-semicomplete digraphs, asymmetric 3-quasi-transitive digraphs and asymmetric 3-anti-quasi-transitive \(TT_3\)-free digraphs. In this paper, we shall completely characterize the above four classes CKI-digraphs without any restriction on arcs and \(TT_3\)-free subdigraphs.
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The author thanks the anonymous referees for several helpful comments.
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This work is supported by the National Natural Science Foundation for Young Scientists of China (11401354)(11501490)(11501341).
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Wang, R. Critical Kernel Imperfect Problem in Generalizations of Bipartite Tournaments. Graphs and Combinatorics 35, 669–675 (2019). https://doi.org/10.1007/s00373-019-02022-5
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DOI: https://doi.org/10.1007/s00373-019-02022-5
Keywords
- Kernel
- CKI-digraph
- Generalization of bipartite tournaments
- Arc-locally in-semicomplete digraph
- 3-Quasi-transitive digraph
- 3-Anti-quasi-transitive digraph