نتایج جستجو برای: steiner distance in graph

تعداد نتایج: 17029596  

2000
Guohui Lin Tao Jiang Paul E. Kearney

Given a graph G = (V; E) and a positive integer k, the Phylogenetic k-Root Problem asks for a (unrooted) tree T without degree-2 nodes such that its leaves are labeled by V and (u; v) 2 E if and only if dT (u; v) k. If the vertices in V are also allowed to be internal nodes in T , then we have the Steiner k-Root Problem. Moreover, if a particular subset S of V are required to be internal nodes ...

Journal: :J. Discrete Algorithms 2015
Ahmad Biniaz Anil Maheshwari Michiel H. M. Smid

Given a weighted graph G = (V,E) and a subset R of V , a Steiner tree in G is a tree which spans all vertices in R. The vertices in V \R are called Steiner vertices. A full Steiner tree is a Steiner tree in which each vertex of R is a leaf. The full Steiner tree problem is to find a full Steiner tree with minimum weight. The bottleneck full Steiner tree problem is to find a full Steiner tree wh...

Journal: :Inf. Process. Lett. 2002
Guohui Lin Guoliang Xue

We investigate a practical variant of the well-known graph Steiner tree problem. In this variant, every target vertex is required to be a leaf vertex in the solution Steiner tree. We present hardness results for this variant as well as a polynomial time approximation algorithm with performance ratio ρ + 2, where ρ is the best-known approximation ratio for the graph Steiner tree problem.  2002 ...

Journal: :Advances in Applied Mathematics 2016

Journal: :Discrete Mathematics 2002

Journal: :transactions on combinatorics 2015
doost ali mojdeh a. sayed-khalkhali hossein abdollahzadeh ahangar yancai zhao

a set $s$ of vertices in a graph $g=(v,e)$ is called a total$k$-distance dominating set if every vertex in $v$ is withindistance $k$ of a vertex in $s$. a graph $g$ is total $k$-distancedomination-critical if $gamma_{t}^{k} (g - x) < gamma_{t}^{k}(g)$ for any vertex $xin v(g)$. in this paper,we investigate some results on total $k$-distance domination-critical of graphs.

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه یزد - دانشکده زبانهای خارجی 1391

the speech act of disagreement has been one of the speech acts that has received the least attention in the field of pragmatics. this study investigates the ways power relations, social distance, formality of the context, gender, and language proficiency (for efl learners) influence disagreement and politeness strategies. the participants of the study were 200 male and female native persian s...

Journal: :iranian journal of mathematical chemistry 2011
a. heydari

let g be a simple connected graph and {v1, v2, …, vk} be the set of pendent (vertices ofdegree one) vertices of g. the reduced distance matrix of g is a square matrix whose (i,j)–entry is the topological distance between vi and vj of g. in this paper, we obtain the spectrumof the reduced distance matrix of thorn graph of g, a graph which obtained by attaching somenew vertices to pendent vertice...

Journal: :Discrete Mathematics 2003
Peter Danziger Eric Mendelsohn

In this paper we introduce the notion of a bicolour graph of a Steiner triple system. Given an arbitrary colouring of the points of a Steiner triple system, the bicolour graph is the graph obtained on the point set of the system by placing an edge between two points if they have the same colour and appear in a triple with a point of a di4erent colour. The case where the graph is Kv was partiall...

2018
Pavel Dvorák Andreas Emil Feldmann Dusan Knop Tomás Masarík Tomas Toufar Pavel Veselý

We study the Steiner Tree problem, in which a set of terminal vertices needs to be connected in the cheapest possible way in an edge-weighted graph. This problem has been extensively studied from the viewpoint of approximation and also parametrization. In particular, on one hand Steiner Tree is known to be APX-hard, and W[2]-hard on the other, if parameterized by the number of non-terminals (St...

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