路径P1,...,称图G=(V,E)中的Pk是相互诱导的,如果对任意1 <= i < j <= k,Pi和Pj既没有公共点也没有相邻点(可能除了它们的端点).导出不相交路问题是检验一个具有k对指定顶点(si,ti)的图G是否包含k条相互导出的路Pi,使得Pi连接si和ti,i=1,.,K.我们表明,这个问题是固定参数的易处理的无爪图时,参数为k。几个相关的问题,如k-in-a-Path问题,被证明是固定参数易处理的无爪图以及。我们表明,这些结果在某些方向上的改进是不可能的,例如,注意到,诱导不相交路径问题不能有一个多项式核线图(一类无爪图),除非NP \subseteq coNP/聚。而且,对于更一般的K_1,4-free图,即使当k=2时,问题也是NP-完全的.最后,我们证明了Fiala等人的n^O(k)-时间算法对于无爪图是否包含k-顶点图H作为拓扑诱导子式的问题是本质最优的,即使G和H是线图,这个问题也是W[1]-困难的.
英文摘要:
Paths P1,...,Pk in a graph G=(V,E) are said to be mutually induced if for any 1 <= i < j <= k, Pi and Pj have neither common vertices nor adjacent vertices (except perhaps their end-vertices). The Induced Disjoint Paths problem is to test whether a graph G with k pairs of specified vertices (si,ti) contains k mutually induced paths Pi such that Pi connects si and ti for i=1,...,k. We show that this problem is fixed-parameter tractable for claw-free graphs when parameterized by k. Several related problems, such as the k-in-a-Path problem, are proven to be fixed-parameter tractable for claw-free graphs as well. We show that an improvement of these results in certain directions is unlikely, for example by noting that the Induced Disjoint Paths problem cannot have a polynomial kernel for line graphs (a type of claw-free graphs), unless NP \subseteq coNP/poly. Moreover, the problem becomes NP-complete, even when k=2, for the more general class of K_1,4-free graphs. Finally, we show that the n^O(k)-time algorithm of Fiala et al. for testing whether a claw-free graph contains some k-vertex graph H as a topological induced minor is essentially optimal by proving that this problem is W[1]-hard even if G and H are line graphs.
Packing 3-vertex paths in claw-free graphs and related topics
图G的一个L-因子是G的一个生成子图,它的每个分支都是一条3-顶点路,设v(G)是G的顶点数,d(G)是G的控制数。爪是一个有四个顶点和三条边关联到同一个顶点的图。一个图是无爪的,如果它没有与爪同构的诱导子图。我们的研究结果包括以下内容。设G是一个3-连通无爪图,x是G中的一个顶点,e = xy是G中的一条边,P是G中的一条3-顶点路.则(a1)如果v(G)= 0 mod 3,则G有一个L-因子,(避免)e,(a2)如果v(G)= 1 mod 3,则G-x具有L-因子,(a3)如果v(G)= 2 mod 3,则G - {x,y}具有L-因子,(a4)如果v(G)= 0 mod 3并且G是立方或4-连通的,则G-P具有L-因子,(a5)若G是三次图,且v(G)> 5,E是G中的三条边的集合,则G - E有L-因子当且仅当G中由E导出的子图不是爪形也不是三角形,(a6)若v(G)= 1 mod 3,则G - {v,e}对G中的每个顶点v和每条边e都有L-因子,(a7)若v(G)= 1 mod 3,则G中存在4-顶点路N和爪Y,使得G-N和G-Y具有L-因子,且(a8)d(G)< v(G)/3 + 1.另外,若G不是圈且v(G)= 1 mod 3,则d(G)< v(G)/3.本文研究了图的填充问题与线图的填充问题之间的关系,得到了关于不同类型填充的一些结果。我们还讨论了L-填充和控制问题…
Let $G=(V,E)$ be a multigraph with a set $T\subseteq V$ of terminals. A path in $G$ is called a $T$-path if its ends are distinct vertices in $T$ and no internal vertices belong to $T$. In 1978, Mader showed a characterization of the maximum number of edge-disjoint $T$-paths. In this paper, we provide a combinatorial, deterministic algorithm for finding the maximum number of edge-disjoint $T$-paths. The algorithm adopts an augmenting path approach. More specifically, we utilize a new concept of short augmenting walks in auxiliary labeled graphs to capture a possible augmentation of the number …
On the Parameterized Tractability of Packing Vertex-Disjoint A-Paths with Length Constraints
Tata Institute of Fundamental Research(塔塔基础研究所);National Institute of Science, Education and Research(国家科学教育与研究学院);Indraprastha Institute of Information Technology Delhi(德里因德拉普拉斯塔信息技术学院)
A temporal graph has an edge set that may change over discrete time steps, and a temporal path (or walk) must traverse edges that appear at increasing time steps. Accordingly, two temporal paths (or walks) are temporally disjoint if they do not visit any vertex at the same time. The study of the computational complexity of finding temporally disjoint paths or walks in temporal graphs has recently been initiated by Klobas et al. [IJCAI '21]. This problem is motivated by applications in multi-agent path finding (MAPF), which include robotics, warehouse management, aircraft management, and traffi…
Making Higher Order MOT Scalable: An Efficient Approximate Solver for Lifted Disjoint Paths
Max Planck Institute for Informatics(马克斯·普朗克信息学研究所);Saarland Informatics Campus(萨尔兰信息学园区);Institute for Information Processing, Leibniz University Hannover(莱布尼茨汉诺威大学信息处理研究所);Max Planck Institute for Intelligent Systems(马克斯·普朗克智能系统研究所)