Journal of the Operations Research Society of China ›› 2025, Vol. 13 ›› Issue (2): 555-573.doi: 10.1007/s40305-023-00474-4

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Two-Disjoint-Cycle-Cover Pancyclicity of Augmented Cubes

Shu-Jie Zhou1,2, Min Xu1,2   

  1. 1. School of Mathematical Sciences, Beijing Normal University, Beijing 100091, China;
    2. Laboratory of Mathematics and Complex Systems, Ministry of Education, Beijing 100875, China
  • Received:2022-08-26 Revised:2023-02-13 Online:2025-06-30 Published:2025-07-07
  • Contact: Min Xu E-mail:xum@bnu.edu.cn

Abstract: A graph G is two-disjoint-cycle-cover \begin{document}$ [r_{1},r_{2}] $\end{document}-pancyclic, if for any integer \begin{document}$ \ell $\end{document} satisfying \begin{document}$ r_{1} \leqslant \ell \leqslant r_{2} $\end{document}, there exist two vertex-disjoint cycles \begin{document}$ C_{1} $\end{document} and \begin{document}$ C_{2} $\end{document} in G such that the lengths of \begin{document}$ C_{1} $\end{document} and \begin{document}$ C_{2} $\end{document} are \begin{document}$ \ell $\end{document} and \begin{document}$ |V(G)|-\ell $\end{document}, respectively, where |V(G)| denotes the number of vertices in G. More specifically, a graph G is two-disjoint-cycle-cover vertex \begin{document}$ [r_{1},r_{2}] $\end{document}-pancyclic (resp. edge \begin{document}$ [r_{1},r_{2}] $\end{document}-pancyclic) if for any two distinct vertices \begin{document}$ u_{1}, u_{2} \in V(G) $\end{document} (resp. two vertex-disjoint edges \begin{document}$ e_{1}, e_{2} \in E(G) $\end{document}), there exist two vertex-disjoint cycles \begin{document}$ C_{1} $\end{document} and \begin{document}$ C_{2} $\end{document} in G such that for every integer \begin{document}$ \ell $\end{document} satisfying \begin{document}$ r_{1} \leqslant \ell \leqslant r_{2} $\end{document}, \begin{document}$ C_{1} $\end{document} contains \begin{document}$ u_{1} $\end{document} (resp. \begin{document}$ e_{1} $\end{document}) with length \begin{document}$ \ell $\end{document} and \begin{document}$ C_{2} $\end{document} contains \begin{document}$ u_{2} $\end{document} (resp. \begin{document}$ e_{2} $\end{document}) with length \begin{document}$ |V(G)|-\ell $\end{document}. In this paper, we consider the problem of two-disjoint-cycle-cover pancyclicity of the n-dimensional augmented cube \begin{document}$ AQ_n $\end{document} and obtain the following results: \begin{document}$ AQ_n $\end{document} is two-disjoint-cycle-cover \begin{document}$ [3,2^{n-1}] $\end{document}-pancyclic for \begin{document}$ n \geqslant 3 $\end{document}. Moreover, \begin{document}$ AQ_n $\end{document} is two-disjoint-cycle-cover vertex \begin{document}$ [3,2^{n-1}] $\end{document}-pancyclic for \begin{document}$ n \geqslant 3 $\end{document}, and \begin{document}$ AQ_n $\end{document} is two-disjoint-cycle-cover edge \begin{document}$ [4,2^{n-1}] $\end{document}-pancyclic for \begin{document}$ n \geqslant 3 $\end{document}.

Key words: Pancyclic, Vertex-disjoint cycles, Disjoint-cycle cover, Augmented cube

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