If D is a digraph, then K∈V(D) is a quasi-kernel of D if D[K]is discrete and for each y∈V(D)-K there is x∈K such that the directed distance from y to x is less than three. We give formulae for the number of quasi-k...If D is a digraph, then K∈V(D) is a quasi-kernel of D if D[K]is discrete and for each y∈V(D)-K there is x∈K such that the directed distance from y to x is less than three. We give formulae for the number of quasi-kernels and for the number of minimal quasi-kernels of oriented paths and cycles.展开更多
文摘If D is a digraph, then K∈V(D) is a quasi-kernel of D if D[K]is discrete and for each y∈V(D)-K there is x∈K such that the directed distance from y to x is less than three. We give formulae for the number of quasi-kernels and for the number of minimal quasi-kernels of oriented paths and cycles.
基金partially supported by the Fundamental Research Funds for the Central Universities,Nankai Universitypartially supported by NSFC(Nos.12161141006,12111540249)+2 种基金the Natural Science Foundation of Tianjin(No.20JCJQJC00090)the Fundamental Research Funds for the Central Universities,Nankai Universitypartially supported by grant DFF-7014-00037B of Independent Research Fund Denmark。
