A module of a graph G is a set of vertices that have the same set of neighbours outside. Modules of a graphs form a so-called partitive family and thereby can be represented by a unique tree MD(G), called the modular decomposition tree. Motivated by the central role of modules in numerous algorithmic graph theory questions, the problem of efficiently computing MD(G) has been investigated since the early 70's. To date the best algorithms run in linear time but are all rather complicated. By combining previous algorithmic paradigms developed for the problem, we are able to present a simpler linear-time that relies on very simple data-structures, namely slice decomposition and sequences of rooted ordered trees.
翻译:图G的一个模块是具有相同外部邻居集合的顶点集。图的模块构成所谓的划分族,从而可表示为唯一树MD(G),称为模块分解树。受模块在诸多算法图论问题中核心作用的驱动,自20世纪70年代初以来,高效计算MD(G)的问题便受到持续研究。迄今为止最优算法均能在线性时间内运行,但都相当复杂。通过整合针对该问题开发的已有算法范式,我们提出了一种更简洁的线性时间算法,该算法仅依赖非常简单的数据结构,即切片分解和有序有根树的序列。