有向圈的笛卡尔积有向图的双控制数

Let γ*(D) denote the twin domination number of digraph D and let Cm Cn denote the Cartesian product of C_m and C_n, the directed cycles of length m, n ≥ 2. In this paper, we determine the exact values: γ*(C_2?C_n) = n; γ*(C_3 ?C_n) = n if n ≡ 0(mod 3),otherwise, γ*(C_3?C_n) = n + 1; γ*(C_4?C_n) = n + n/2 if n ≡ 0, 3, 5(mod 8), otherwise,γ*(C_4?C_n) = n + n/2 + 1; γ*(C_5?C_n) = 2n; γ*(C_6?C_n) = 2n if n ≡ 0(mod 3), otherwise,γ*(C_6?C_n) = 2n + 2.

The Twin Domination Number of Cartesian Product of Directed Cycles

Let $\gamma^{*}(D)$ denote the twin domination number of digraph $D$ and let $C_{m}\square C_{n}$ denote the Cartesian product of $C_{m}$ and $C_{n}$, the directed cycles of length $m, n\geq 2$. In this paper, we determine the exact values: $\gamma^{*}(C_{2}\square C_{n})=n$; $\gamma^{*}(C_{3}\square C_{n})=n$ if $n\equiv 0~({\rm mod}\,3)$, otherwise, $\gamma^{*}(C_{3}\square C_{n})=n+1$; $\gamma^{*}(C_{4}\square C_{n})=n+\lceil\frac{n}{2}\rceil$ if $n\equiv 0,3,5~({\rm mod}\,8)$, otherwise, $\gamma^{*}(C_{4}\square C_{n})=n+\lceil\frac{n}{2}\rceil+1$; $\gamma^{*}(C_{5}\square C_{n})=2n$; $\gamma^{*}(C_{6}\square C_{n})=2n$ if $n\equiv 0~({\rm mod}\,3)$, otherwise, $\gamma^{*}(C_{6}\square C_{n})=2n+2$.