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The \textit{longest path transversal number} of a connected graph $G$, denoted by $lpt(G)$, is the minimum size of a set of vertices of $G$ that intersects all longest paths in $G$. We present constant upper bounds for the longest path…

Combinatorics · Mathematics 2025-10-23 Paloma T. de Lima , Amir Nikabadi , Paweł Rzążewski

Let $G=(V,E)$ be a complete $n$-vertex graph with distinct positive edge weights. We prove that for $k\in\{1,2,...,n-1\}$, the set consisting of the edges of all minimum spanning trees (MSTs) over induced subgraphs of $G$ with $n-k+1$…

Combinatorics · Mathematics 2007-05-23 Gregory B. Sorkin , Angelika Steger , Rico Zenklusen

We introduce and investigate a new notion of resilience in graph spanners. Let $S$ be a spanner of a graph $G$. Roughly speaking, we say that a spanner $S$ is resilient if all its point-to-point distances are resilient to edge failures.…

Data Structures and Algorithms · Computer Science 2014-05-30 G. Ausiello , P. G. Franciosa , G. F. Italiano , A. Ribichini

The twin-width of a graph $G$ is the minimum integer $d$ such that $G$ has a $d$-contraction sequence, that is, a sequence of $|V(G)|-1$ iterated vertex identifications for which the overall maximum number of red edges incident to a single…

Discrete Mathematics · Computer Science 2020-06-18 Édouard Bonnet , Colin Geniet , Eun Jung Kim , Stéphan Thomassé , Rémi Watrigant

Let $G$ be a connected graph and $u,v$ and $w$ vertices of $G$. Then $w$ is said to {\em strongly resolve} $u$ and $v$, if there is either a shortest $u$-$w$ path that contains $v$ or a shortest $v$-$w$ path that contains $u$. A set $W$ of…

Combinatorics · Mathematics 2020-08-11 Nadia Benakli , Novi H Bong , Shonda M. Dueck , Linda Eroh , Beth Novick , Ortrud R. Oellermann

For their famous algorithm for the disjoint paths problem, Robertson and Seymour proved that there is a function $f$ such that if the tree-width of a graph $G$ with $k$ pairs of terminals is at least $f(k)$, then $G$ contains a…

Discrete Mathematics · Computer Science 2019-01-15 Isolde Adler , Philipp Klaus Krause

Consider~\(n\) nodes~\(\{X_i\}_{1 \leq i \leq n}\) independently distributed in the unit square~\(S,\) each according to a distribution~\(f.\) Nodes~\(X_i\) and~\(X_j\) are joined by an edge if the Euclidean distance~\(d(X_i,X_j)\) is less…

Probability · Mathematics 2021-03-02 Ghurumuruhan Ganesan

Rigidity is the property of a structure that does not flex. It is well studied in discrete geometry and mechanics, and has applications in material science, engineering and biological sciences. A bar-and-joint framework is a pair $(G,p)$ of…

Combinatorics · Mathematics 2021-03-02 Sebastian M. Cioabă , Sean Dewar , Xiaofeng Gu

Let $G$ be a connected graph and $T$ a spanning tree of $G$. Let $\rho(G)$ denote the adjacency spectral radius of $G$. The $k$-excess of a vertex $v$ in $T$ is defined as $\max\{0,d_T(v)-k\}$. The total $k$-excess $\mbox{te}(T,k)$ is…

Combinatorics · Mathematics 2026-03-24 Sizhong Zhou

Twin-width is a newly introduced graph width parameter that aims at generalizing a wide range of "nicely structured" graph classes. In this work, we focus on obtaining good bounds on twin-width $\text{tww}(G)$ for graphs $G$ from a number…

Discrete Mathematics · Computer Science 2022-01-25 Hugo Jacob , Marcin Pilipczuk

A graph $G$ contains a graph $H$ as an induced minor if $H$ can be obtained from $G$ after vertex deletions and edge contractions. We show that for every $k$-vertex planar graph $H$, every graph $G$ excluding $H$ as an induced minor and…

Combinatorics · Mathematics 2024-07-23 Édouard Bonnet , Jędrzej Hodor , Tuukka Korhonen , Tomáš Masařík

The threshold-$k$ metric dimension ($\mathrm{Tmd}_k$) of a graph is the minimum number of sensors -- a subset of the vertex set -- needed to uniquely identify any vertex in the graph, solely based on its distances from the sensors, when the…

Combinatorics · Mathematics 2021-11-18 Zsolt Bartha , Júlia Komjáthy , Järvi Raes

A dynamic graph algorithm is a data structure that answers queries about a property of the current graph while supporting graph modifications such as edge insertions and deletions. Prior work has shown strong conditional lower bounds for…

Data Structures and Algorithms · Computer Science 2023-01-30 Monika Henzinger , Ami Paz , A. R. Sricharan

Decision trees are important both as interpretable models amenable to high-stakes decision-making, and as building blocks of ensemble methods such as random forests and gradient boosting. Their statistical properties, however, are not well…

Machine Learning · Statistics 2021-10-20 Yan Shuo Tan , Abhineet Agarwal , Bin Yu

Let $d_u$ be the degree of a vertex $u$ of a graph $G$. The atom-bond sum-connectivity (ABS) index of a graph $G$ is the sum of the numbers $(1-2(d_v+d_w)^{-1})^{1/2}$ over all edges $vw$ of $G$. This paper gives the characterization of the…

Minimum spanning trees are important tools in the analysis and design of networks. Many practical applications require their computation, ranging from biology and linguistics to economy and telecommunications. The set of cycles of a network…

Discrete Mathematics · Computer Science 2024-04-29 Manuel Dubinsky , Kun-Mao Chao , César Massri , Gabriel Taubin

Let $T$ be a tree, a vertex of degree one is a leaf of $T$ and a vertex of degree at least three is a branch vertex of $T$. For two distinct vertices $u,v$ of $T$, let $P_T[u,v]$ denote the unique path in $T$ connecting $u$ and $v.$ For a…

Combinatorics · Mathematics 2021-12-09 Pham Hoang Ha

In 1989, Zehavi and Itai conjectured that every $k$-connected graph contains $k$ independent spanning trees rooted at any prescribed vertex $r$. That is, for each vertex $v$, the unique $r$-$v$ paths within these $k$ spanning trees are…

A spanner is a sparse subgraph of a given graph $G$ which preserves distances, measured w.r.t.\ some distance metric, up to a multiplicative stretch factor. This paper addresses the problem of constructing graph spanners w.r.t.\ the group…

Data Structures and Algorithms · Computer Science 2024-07-02 Davide Bilò , Luciano Gualà , Stefano Leucci , Alessandro Straziota

We study the existence and construction of sparse supports for hypergraphs derived from subgraphs of a graph $G$. For a hypergraph $(X,\mathcal{H})$, a support $Q$ is a graph on $X$ s.t. $Q[H]$, the graph induced on vertices in $H$ is…

Combinatorics · Mathematics 2025-06-10 Rajiv Raman , Karamjeet Singh