In this paper, we are interested in the edge intersection graphs of paths of a grid where each path has at most one bend, called B1-EPG graphs and first introduced by Golumbic et al (2009). We also consider a proper subclass of B1-EPG, the L-EPG graphs, which allows paths only in ``L'' shape. We show that two superclasses of trees are B1-EPG (one of them being the cactus graphs). On the other hand, we show that the block graphs are L-EPG and provide a linear time algorithm to produce L-EPG representations of generalization of trees. These proofs employed a new technique from previous results in the area based on block-cutpoint trees of the respective graphs.
翻译:在本文中,我们感兴趣的是每个路径最多有一个弯曲的网格路径的边缘交叉图,称为B1-EPG图,首先由Golumbic等人介绍(2009年)。我们还考虑一个合适的小类,即L-EPG图,它只允许“L”形状的路径。我们显示两个超级树类是B1-EPG(其中一个是仙人掌图)。另一方面,我们显示区块图是L-EPG,提供了一种线性时间算法,以产生L-EPG对树木的概括性表示。这些证明采用了基于各图形区块截线树的区域内先前结果的新方法。