论文标题

Turán数字和反斑点的短周期,完整的3美元 - 明确图

Turán numbers and anti-Ramsey numbers for short cycles in complete $3$-partite graphs

论文作者

Fang, Chunqiu, Győri, Ervin, Xiao, Chuanqi, Xiao, Jimeng

论文摘要

我们将$ 4 $ - 循环称为$ k_ {n_ {1},n_ {2},n_ {3}} $ suptratite,由$ c_ {4}^{\ text {multi}} $表示,如果它至少包含$ k_ {n _ {1}的每个部分, n_ {3}} $。 turán数字$ \ text {ex}(k_ {n_ {1},n_ {2},n_ {3}},c_ {4}^{\ text {\ text {multi}}} $ \ text {ex}(k_ {n_ {1},n_ {2},n_ {3}},\ {c_ {3},c_ {4}^{\ text {\ text {multi}}}}} \} \})$ k_ {n_ {1},n_ {2},n_ {3}} $,以至于$ g $包含no $ c_ {4}^{\ text {\ text {multi}} $ $ \ bigg($分别,$ g $,$ g $都不包含$ c_ c_ {3} $ c_ {3} $ c_ nor $ c_ n} $ {4} $}如果所有四个边缘都有不同的颜色,我们将其称为$ c^{multi} _4 $彩虹。 Ant-ramsey数$ \ text {ar}(k_ {n_ {1},n_ {2},n_ {3}},c_ {4}^{\ text {multi}}} $是$ k_ {n n n n n n n n n n n n n n n n n n n n n no n n n n n n n n n n n n n no {1},n _ {2},n _ {2) $ c_ {4}^{\ text {multi}} $。在本文中,我们确定$ \ text {ex}(k_ {n_ {1},n_ {2},n_ {3}},c_ {4}^{\ text {multi}}} $ \ text {ar}(k_ {n_ {1},n_ {2},n_ {3}},c_ {4}^{\ text {\ text {multi}})= \ text {ex} c_ {4}^{\ text {multi}} \})+1 = n_ {1} n_ {2}+n_ {3}+1,$ n_ {1} \ ge n_ {2} \ ge n_ {2}

We call a $4$-cycle in $K_{n_{1}, n_{2}, n_{3}}$ multipartite, denoted by $C_{4}^{\text{multi}}$, if it contains at least one vertex in each part of $K_{n_{1}, n_{2}, n_{3}}$. The Turán number $\text{ex}(K_{n_{1},n_{2},n_{3}}, C_{4}^{\text{multi}})$ $\bigg($ respectively, $\text{ex}(K_{n_{1},n_{2},n_{3}},\{C_{3}, C_{4}^{\text{multi}}\})$ $\bigg)$ is the maximum number of edges in a graph $G\subseteq K_{n_{1},n_{2},n_{3}}$ such that $G$ contains no $C_{4}^{\text{multi}}$ $\bigg($ respectively, $G$ contains neither $C_{3}$ nor $C_{4}^{\text{multi}}$ $\bigg)$. We call a $C^{multi}_4$ rainbow if all four edges of it have different colors. The ant-Ramsey number $\text{ar}(K_{n_{1},n_{2},n_{3}}, C_{4}^{\text{multi}})$ is the maximum number of colors in an edge-colored of $K_{n_{1},n_{2},n_{3}}$ with no rainbow $C_{4}^{\text{multi}}$. In this paper, we determine that $\text{ex}(K_{n_{1},n_{2},n_{3}}, C_{4}^{\text{multi}})=n_{1}n_{2}+2n_{3}$ and $\text{ar}(K_{n_{1},n_{2},n_{3}}, C_{4}^{\text{multi}})=\text{ex}(K_{n_{1},n_{2},n_{3}}, \{C_{3}, C_{4}^{\text{multi}}\})+1=n_{1}n_{2}+n_{3}+1,$ where $n_{1}\ge n_{2}\ge n_{3}\ge 1.$

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