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We initiate the study of a fundamental combinatorial problem: Given a capacitated graph $G=(V,E)$, find a shortest walk ("route") from a source $s\in V$ to a destination $t\in V$ that includes all vertices specified by a set…

Data Structures and Algorithms · Computer Science 2018-05-01 Saeed Akhoondian Amiri , Klaus-Tycho Foerster , Stefan Schmid

We study approaches for the exact solution of the \NP--hard minimum spanning tree problem under conflict constraints. Given a graph $G(V,E)$ and a set $C \subset E \times E$ of conflicting edge pairs, the problem consists of finding a…

Data Structures and Algorithms · Computer Science 2014-07-01 Phillippe Samer , Sebastián Urrutia

Intersection graphs are well-studied in the area of graph algorithms. Some intersection graph classes are known to have algorithms enumerating all unlabeled graphs by reverse search. Since these algorithms output graphs one by one and the…

Data Structures and Algorithms · Computer Science 2022-12-15 Jun Kawahara , Toshiki Saitoh , Hirokazu Takeda , Ryo Yoshinaka , Yui Yoshioka

We show that for any fixed dense graph G and bounded-degree tree T on the same number of vertices, a modest random perturbation of G will typically contain a copy of T . This combines the viewpoints of the well-studied problems of embedding…

Combinatorics · Mathematics 2025-05-30 Michael Krivelevich , Matthew Kwan , Benny Sudakov

In a graph G, a dissociation set is a subset of vertices which induces a subgraph with vertex degree at most 1. Finding a dissociation set of maximum cardinality in a graph is NP-hard even for bipartite graphs and is called the maximum…

Combinatorics · Mathematics 2021-08-02 Jianhua Tu , Lei Zhang , Junfeng Du , Rongling Lang

Let claw be the graph $K_{1,3}$. A graph $G$ on $n\geq 3$ vertices is called \emph{o}-heavy if each induced claw of $G$ has a pair of end-vertices with degree sum at least $n$, and 1-heavy if at least one end-vertex of each induced claw of…

Combinatorics · Mathematics 2014-06-23 Bo Ning , Shenggui Zhang , Bing Chen

A dominating set of a graph $G$ is a set $D\subseteq V_G$ such that every vertex in $V_G-D$ is adjacent to at least one vertex in $D$, and the domination number $\gamma(G)$ of $G$ is the minimum cardinality of a dominating set of $G$. A set…

Combinatorics · Mathematics 2021-01-18 Andrzej Lingas , Mateusz Miotk , Jerzy Topp , Paweł Żyliński

For a graph $H$, a graph $G$ is an $H$-graph if it is an intersection graph of connected subgraphs of some subdivision of $H$. $H$-graphs naturally generalize several important graph classes like interval or circular-arc graph. This class…

Data Structures and Algorithms · Computer Science 2020-02-24 Fedor V. Fomin , Petr A. Golovach , Jean-Florent Raymond

We study the Hamiltonian path problem in C-shaped grid graphs, and present the necessary and sufficient conditions for the existence of a Hamiltonian path between two given vertices in these graphs. We also give a linear-time algorithm for…

Computational Complexity · Computer Science 2016-02-25 Fatemeh Keshavarz-Kohjerdi , Alireza Bagheri

In the present paper, we study algorithmic questions for the arc-intersection graph of directed paths on a tree. Such graphs are known to be perfect (proved by Monma and Wei in 1986). We present faster algorithms than all previously known…

Discrete Mathematics · Computer Science 2009-02-10 Olivier Durand de Gévigney , Frédéric Meunier , Christian Popa , Julien Reygner , Ayrin Romero

We introduce and study the complexity of Path Packing. Given a graph $G$ and a list of paths, the task is to embed the paths edge-disjoint in $G$. This generalizes the well known Hamiltonian-Path problem. Since Hamiltonian Path is…

Computational Complexity · Computer Science 2019-10-02 Jan Dreier , Janosch Fuchs , Tim A. Hartmann , Philipp Kuinke , Peter Rossmanith , Bjoern Tauer , Hung-Lung Wang

We study the parameterized complexity of dominating sets in geometric intersection graphs. In one dimension, we investigate intersection graphs induced by translates of a fixed pattern Q that consists of a finite number of intervals and a…

Computational Geometry · Computer Science 2017-09-18 Mark de Berg , Sándor Kisfaludi-Bak , Gerhard Woeginger

A graph is locally chordal if each of its small-radius balls is chordal. In an earlier work [AKK25], the authors and Kobler proved that locally chordal graphs can be characterized by having chordal local covers, by forbidding short cycles…

Combinatorics · Mathematics 2025-12-23 Tara Abrishami , Paul Knappe

An (h,s,t)-representation of a graph G consists of a collection of subtrees of a tree T, where each subtree corresponds to a vertex of G such that (i) the maximum degree of T is at most h, (ii) every subtree has maximum degree at mots s,…

Combinatorics · Mathematics 2011-12-15 Liliana Alcón , Marisa Gutierrez , María Pía Mazzoleni

Chordal graphs form one of the most studied graph classes. Several graph problems that are NP-hard in general become solvable in polynomial time on chordal graphs, whereas many others remain NP-hard. For a large group of problems among the…

Discrete Mathematics · Computer Science 2018-11-01 Oylum Şeker , Pinar Heggernes , Tınaz Ekim , Z. Caner Taşkın

Say that an edge of a graph $G$ dominates itself and every other edge adjacent to it. An edge dominating set of a graph $G=(V,E)$ is a subset of edges $E' \subseteq E$ which dominates all edges of $G$. In particular, if every edge of $G$ is…

Data Structures and Algorithms · Computer Science 2013-03-07 Min Chih Lin , Michel J. Mizrahi , Jayme L. Szwarcfiter

Given a graph $G$ and a graph property $P$ we say that $G$ is minimal with respect to $P$ if no proper induced subgraph of $G$ has the property $P$. An HC-obstruction is a minimal 2-connected non-Hamiltonian graph. Given a graph $H$, a…

Combinatorics · Mathematics 2023-01-04 Aristotelis Chaniotis , Zishen Qu , Sophie Spirkl

We investigate the problem of simultaneously dominating all spanning trees of a given graph. We prove that on 2-connected graphs, a subset of the vertices dominates all spanning trees of the graph if and only if it is a vertex cover. Using…

Combinatorics · Mathematics 2020-12-17 Sebastian S. Johann , Sven O. Krumke , Manuel Streicher

Modern graph or network datasets often contain rich structure that goes beyond simple pairwise connections between nodes. This calls for complex representations that can capture, for instance, edges of different types as well as so-called…

Social and Information Networks · Computer Science 2020-02-19 Ilya Amburg , Nate Veldt , Austin R. Benson

IC-planar graphs are those graphs that admit a drawing where no two crossed edges share an end-vertex and each edge is crossed at most once. They are a proper subfamily of the 1-planar graphs. Given an embedded IC-planar graph $G$ with $n$…

Computational Geometry · Computer Science 2016-07-19 Franz J. Brandenburg , Walter Didimo , William S. Evans , Philipp Kindermann , Giuseppe Liotta , Fabrizio Montecchiani