arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 1107.0207math.COcs.DM
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识别线图中的代码

Identifying codes in line graphs

Florent Foucaud, Sylvain Gravier, Reza Naserasr, Aline Parreau, Petru Valicov

摘要:

图的标识码是图的顶点的子集,使得图的每个顶点都由其在码内的邻居的集合唯一地标识。研究了边识别码问题,即线图中的识别码问题。如果$\ID(G)$表示可识别图$G$的最小识别码的大小,我们证明了通常的界$\ID(G)\ge \lceil\log_2(n+1)\rceil$,其中$n$表示$G$的阶,在线图类中可以改进为$Θ(\sqrt{n})$.而且,这个界限很紧。我们还证明了上界$\ID(\mathcal{L}(G))\leq 2|V(G)|-5$,其中$\mathcal{L}(G)$是线图的$G$,持有(有两个例外)。这意味着R. Klasing,A. Kosowski,A. Raspaud和第一作者对于线图的一个子类成立。最后,我们证明了边识别码问题是NP-完全的,即使对于最大度~3和任意大围长的平面二部图也是如此。

英文摘要:

An identifying code of a graph is a subset of its vertices such that every vertex of the graph is uniquely identified by the set of its neighbours within the code. We study the edge-identifying code problem, i.e. the identifying code problem in line graphs. If $\ID(G)$ denotes the size of a minimum identifying code of an identifiable graph $G$, we show that the usual bound $\ID(G)\ge \lceil\log_2(n+1)\rceil$, where $n$ denotes the order of $G$, can be improved to $Θ(\sqrt{n})$ in the class of line graphs. Moreover, this bound is tight. We also prove that the upper bound $\ID(\mathcal{L}(G))\leq 2|V(G)|-5$, where $\mathcal{L}(G)$ is the line graph of $G$, holds (with two exceptions). This implies that a conjecture of R. Klasing, A. Kosowski, A. Raspaud and the first author holds for a subclass of line graphs. Finally, we show that the edge-identifying code problem is NP-complete, even for the class of planar bipartite graphs of maximum degree~3 and arbitrarily large girth.

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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