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arXiv 1006.3779math.COcs.DS
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无限三角网格上点识别码密度的一个新的下界

A New Lower Bound on the Density of Vertex Identifying Codes for the Infinite Hexagonal Grid

Daniel W. Cranston, Gexin Yu

摘要:

给定图$G$,标识码$C \subseteq V(G)$是顶点集,使得对于任何两个不同的顶点$v_1,v_2\in V(G)$,集合$N[v_1]\cap C$和$N[v_2]\cap C$是不同的且非空的(这里$N[v]$表示顶点$v$及其邻居)。我们研究的情况下,当$G$是无限六边形网格$H$。Cohen等人构造了密度为$3/7$的两个$H$识别码,并证明了任何$H$识别码的密度至少为$16/39\approx0.410256$。它们的上界和下界都是迄今为止最为人所知的。这里我们证明了$12/29\approx0.413793$的一个下界。

英文摘要:

Given a graph $G$, an identifying code $C \subseteq V(G)$ is a vertex set such that for any two distinct vertices $v_1,v_2\in V(G)$, the sets $N[v_1]\cap C$ and $N[v_2]\cap C$ are distinct and nonempty (here $N[v]$ denotes a vertex $v$ and its neighbors). We study the case when $G$ is the infinite hexagonal grid $H$. Cohen et.al. constructed two identifying codes for $H$ with density $3/7$ and proved that any identifying code for $H$ must have density at least $16/39\approx0.410256$. Both their upper and lower bounds were best known until now. Here we prove a lower bound of $12/29\approx0.413793$.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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