English
Related papers

Related papers: Extremal trees of given degree sequence or segment…

200 papers

The Steiner $k$-eccentricity of a vertex $v$ of a graph $G$ is the maximum Steiner distance over all $k$-subsets of $V(G)$ which contain $v$. In this paper Steiner $3$-eccentricity is studied on trees. Some general properties of the Steiner…

Combinatorics · Mathematics 2021-07-13 Xingfu Li , Guihai Yu , Sandi Klavžar

The Steiner $k$-eccentricity of a vertex $v$ of a graph $G$ is the maximum Steiner distance over all $k$-subsets of $V (G)$ which contain $v$. In this note, we design a linear algorithm for computing the Steiner $3$-eccentricities and the…

Data Structures and Algorithms · Computer Science 2021-02-23 Aleksandar Ilic

The Steiner $k$-eccentricity of a vertex $v$ of a graph $G$ is the maximum Steiner distance over all $k$-subsets of $V (G)$ which contain $v$. A linear time algorithm for calculating the Steiner $k$-eccentricity of a vertex on block graphs…

Combinatorics · Mathematics 2021-12-03 Xingfu Li , Guihai Yu , Aleksandar Ilić , Sandi Klavžar

Various questions related to distances between vertices of simple, finite graphs are of interest to extremal graph theorists. The Steiner distance of a set of $k$ vertices is a natural generalization of the regular distance. We extend…

Combinatorics · Mathematics 2023-02-07 Hua Wang , Andrew Zhang

We study the Steiner $k$-eccentricity on trees, which generalizes the previous one in the paper [X.~Li, G.~Yu, S.~Klav\v{z}ar, On the average Steiner 3-eccentricity of trees, arXiv:2005.10319, 2020]. To support the algorithm, we achieve…

Combinatorics · Mathematics 2020-08-19 Xingfu Li , Guihai Yu , Sandi Klavžar , Jie Hu , Bo Li

Given a connected graph $G=(V,E)$ and a $k$-set $S\subseteq V(G)$, the $Steiner$ $distance$ $d_{G}(S)$ of $S$ is defined as the size of a minimum tree including $S$ in $G$. The $Steiner$ $k$-$eccentricity$ of a vertex $v$ in $G$ is the…

Combinatorics · Mathematics 2025-12-01 Qingnan Zhang , Yingzhi Tian

The Steiner distance of vertices in a set $S$ is the minimum size of a connected subgraph that contain these vertices. The sum of the Steiner distances over all sets $S$ of cardinality $k$ is called the Steiner $k$-Wiener index and studied…

Combinatorics · Mathematics 2020-08-06 Jie Zhang , Hua Wang , Xiao-Dong Zhang

The eccentricity of a vertex $v$ in a graph $G$ is the maximum distance from $v$ to any other vertex. The vertices whose eccentricity are equal to the diameter (the maximum eccentricity) of $G$ are called peripheral vertices. In trees the…

Combinatorics · Mathematics 2019-09-02 Ya-Hong Chen , Hua Wang , Xiao-Dong Zhang

We study that over some types of trees with a given number of vertices, which trees minimize or maximize the total number of subtrees. Trees minimizing (resp. maximizing) the total number of subtrees usually maximize (resp. minimize) the…

Combinatorics · Mathematics 2012-04-30 Shuchao Li , Shujing Wang

Consider the complete graph on $n$ vertices, with edge weights drawn independently from the exponential distribution with unit mean. Janson showed that the typical distance between two vertices scales as $\log{n}/n$, whereas the diameter…

Probability · Mathematics 2015-07-20 A. Davidson , A. Ganesh

In a connected graph G, the distance between two vertices of G is the length of a shortest path between these vertices. The eccentricity of a vertex u in G is the largest distance between u and any other vertex of G. The total-eccentricity…

Combinatorics · Mathematics 2017-11-21 Rashid Farooq , Mehar Ali Malik , Juan Rada

In this paper we introduce some transformations for trees that do not increase the average Steiner $(k,l)$-eccentricity for all $0\leq l\leq k\leq n$. Using these transformations, we obtain some sharp bounds on the average Steiner…

Combinatorics · Mathematics 2025-07-22 Cheng Zeng , Gengji Li

Let $G=(V_G, E_G)$ be a simple connected graph. The eccentric distance sum of $G$ is defined as $\xi^{d}(G) = \sum_{v\in V_G}\varepsilon_{G}(v)D_{G}(v)$, where $\varepsilon_G(v)$ is the eccentricity of the vertex $v$ and $D_G(v) =…

Combinatorics · Mathematics 2012-07-03 Shuchao Li , Meng Zhang

The eccentricity of a vertex, $ecc_T(v) = \max_{u\in T} d_T(v,u)$, was one of the first, distance-based, tree invariants studied. The total eccentricity of a tree, $Ecc(T)$, is the sum of eccentricities of its vertices. We determine…

Combinatorics · Mathematics 2015-05-12 Heather Smith , László Székely , Hua Wang

The Wiener index of a graph is the sum of the distances between all pairs of vertices, it has been one of the main descriptors that correlate achemical compound's molecular graph with experimentally gathered data regarding the compound's…

Combinatorics · Mathematics 2007-09-12 Hua Wang

The eccentric sequence of a connected graph $G$ is the nondecreasing sequence of the eccentricities of its vertices. The Wiener index of $G$ is the sum of the distances between all unordered pairs of vertices of $G$. The unique trees that…

Combinatorics · Mathematics 2020-05-20 Peter Dankelmann , Audace A. V. Dossou-Olory

The eccentricity of a vertex $u$ in a connected graph $G$ is the distance between $u$ and a vertex farthest from it; the eccentric sequence of $G$ is the nondecreasing sequence of the eccentricities of $G$. In this paper, we determine the…

Combinatorics · Mathematics 2020-02-18 Peter Dankelmann , Audace A. V. Dossou-Olory

Over some types of trees with a given number of vertices, which trees minimize or maximize the total number of subtrees or leaf containing subtrees are studied. Here are some of the main results:\ (1)\, Sharp upper bound on the total number…

Combinatorics · Mathematics 2012-06-15 Shuchao Li , Shujing Wang

A \emph{tree-partition} of a graph $G$ is a proper partition of its vertex set into `bags', such that identifying the vertices in each bag produces a forest. The \emph{tree-partition-width} of $G$ is the minimum number of vertices in a bag…

Combinatorics · Mathematics 2009-04-02 David R. Wood

Given a connected graph $G=(V,E)$ and a vertex set $S\subset V$, the {\em Steiner distance} $d(S)$ of $S$ is the size of a minimum spanning tree of $S$ in $G$. For a connected graph $G$ of order $n$ and an integer $k$ with $2\leq k \leq n$,…

Combinatorics · Mathematics 2020-12-23 Josiah Reiswig
‹ Prev 1 2 3 10 Next ›