Many NP-Hard problems on general graphs, such as maximum independence set, maximal cliques and graph coloring can be solved efficiently on chordal graphs. In this paper, we explore the problem of non-separating st-paths defined on edges: for a connected undirected graph and two vertices, a non-separating path is a path between the two vertices such that if we remove all the edges on the path, the graph remains connected. We show that on general graphs, checking the existence of non-separating st-paths is NP-Hard, but the same problem can be solved in linear time on chordal graphs. In the case that such path exists, we introduce an algorithm that finds the shortest non-separating st-path on a connected chordal graph of $n$ vertices and $m$ edges with positive edge lengths that runs in $O(n\log{n} + m)$ time.
翻译:普通图形上的许多 NP- 硬度问题, 如最大独立设置、 最大 cliques 和 图形颜色等, 可以在 chordal 图形上有效解决 。 在本文中, 我们探讨边缘定义的非分隔路径问题: 对于连接的未定向图形和两个顶点, 一个非分隔路径是两个顶点之间的一条路径, 这样如果我们删除路径上的所有边缘, 图形仍然连接。 我们在普通图形上显示, 检查非分离路径的存在是 NP- Hard, 但相同的问题也可以在 chordal 图形上的线性时间中解决 。 在这条路径存在的情况下, 我们引入一种算法, 在以 $n( n\ { n} + m) 时间运行的连接的 zordal 图形上找到最短的非分离的正边缘端点, 以 $( n\\ { n} + m) 时间运行的 。