论文标题

解析素数模块:伪描绘的结构和可解释的图形

Resolving Prime Modules: The Structure of Pseudo-cographs and Galled-Tree Explainable Graphs

论文作者

Hellmuth, Marc, Scholz, Guillaume E.

论文摘要

图形$ g $的模块化分解是一种自然结构,可在标记的树$(t,t)$方面捕获$ g $的关键特征,其顶点被标记为“系列”($ 1 $),“并行”($ 0 $)或“ prime”。但是,$ g $的全部信息仅由其模块化分解树$(t,t)$提供,如果$ g $是cograph,即$ g $不包含Prime模块。在这种情况下,$(t,t)$解释$ g $,即$ \ {x,x,y \} \ in E(g)$ in E(g)$,并且仅是当时最低的共同祖先$ \ mathrm {lca} _t(x,x,x,y)$ x $的$ x $和$ y $ y $ $ $ $ $ $ $ y label” $ 1 $”。伪描绘,或更通用的Gatex Graphs $ g $是可以通过标记的壁炉树(即标记为网络$(N,T)$来解释的图形,这些图是从模块化分解树$(t,t)$ G $中获得的$ G $的$ g $的$(t)$,通过简单的cycles cycles cycles cycles更换$ g $。可以在线性时间内构建这些图形的Gatex图可以识别并标记为累积的树。 在此贡献中,我们根据集合$ \ mathfrak {f} _ {\ mathrm {gt}} $ 25禁止诱导子图表的$。反过来,这种表征使我们能够证明Gatex图与许多其他知名的图形类别密切相关,例如$ P_4 $ -SPARSE和$ P_4 $ - 可更高的图形,虚弱的图形,具有完美的顺序,可比较性和置换图的完美图形,模糊的图形,模糊的图形,Meyniel图形,间隔图,非常强的图形或非常强的图形和非常强的图形和brirttly-perfects和britterflect。此外,我们表明,每个Gatex图最多在1处为双宽度,并提供线性时间算法,以通过利用基础盖的结构来解决Gatex图上的几个NP硬问题(Clique,Clique,Coloring,独立集),他们解释了。

The modular decomposition of a graph $G$ is a natural construction to capture key features of $G$ in terms of a labeled tree $(T,t)$ whose vertices are labeled as "series" ($1$), "parallel" ($0$) or "prime". However, full information of $G$ is provided by its modular decomposition tree $(T,t)$ only, if $G$ is a cograph, i.e., $G$ does not contain prime modules. In this case, $(T,t)$ explains $G$, i.e., $\{x,y\}\in E(G)$ if and only if the lowest common ancestor $\mathrm{lca}_T(x,y)$ of $x$ and $y$ has label "$1$". Pseudo-cographs, or, more general, GaTEx graphs $G$ are graphs that can be explained by labeled galled-trees, i.e., labeled networks $(N,t)$ that are obtained from the modular decomposition tree $(T,t)$ of $G$ by replacing the prime vertices in $T$ by simple labeled cycles. GaTEx graphs can be recognized and labeled galled-trees that explain these graphs can be constructed in linear time. In this contribution, we provide a novel characterization of GaTEx graphs in terms of a set $\mathfrak{F}_{\mathrm{GT}}$ of 25 forbidden induced subgraphs. This characterization, in turn, allows us to show that GaTEx graphs are closely related to many other well-known graph classes such as $P_4$-sparse and $P_4$-reducible graphs, weakly-chordal graphs, perfect graphs with perfect order, comparability and permutation graphs, murky graphs as well as interval graphs, Meyniel graphs or very strongly-perfect and brittle graphs. Moreover, we show that every GaTEx graph as twin-width at most 1 and and provide linear-time algorithms to solve several NP-hard problems (clique, coloring, independent set) on GaTEx graphs by utilizing the structure of the underlying galled-trees they explain.

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