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A monotone drawing of a graph G is a straight-line drawing of G such that every pair of vertices is connected by a path that is monotone with respect to some direction. Trees, as a special class of graphs, have been the focus of several…

Data Structures and Algorithms · Computer Science 2025-05-19 Anargyros Oikonomou , Antonios Symvonis

We investigate the computational complexity of separating two distinct vertices s and z by vertex deletion in a temporal graph. In a temporal graph, the vertex set is fixed but the edges have (discrete) time labels. Since the corresponding…

Computational Complexity · Computer Science 2020-10-12 Till Fluschnik , Hendrik Molter , Rolf Niedermeier , Malte Renken , Philipp Zschoche

Many scientific datasets are of high dimension, and the analysis usually requires visual manipulation by retaining the most important structures of data. Principal curve is a widely used approach for this purpose. However, many existing…

Artificial Intelligence · Computer Science 2016-01-19 Qi Mao , Li Wang , Ivor W. Tsang , Yijun Sun

A crossing-free straight-line drawing of a graph is monotone if there is a monotone path between any pair of vertices with respect to some direction. We show how to construct a monotone drawing of a tree with $n$ vertices on an $O(n^{1.5})…

Computational Geometry · Computer Science 2016-04-26 Philipp Kindermann , André Schulz , Joachim Spoerhase , Alexander Wolff

In this paper we study the Spanning Tree Congestion problem, where we are given a graph $G=(V,E)$ and are asked to find a spanning tree $T$ of minimum maximum congestion. Here, the congestion of an edge $e\in T$ is the number of edges…

Data Structures and Algorithms · Computer Science 2026-05-28 Michael Lampis , Valia Mitsou , Edouard Nemery , Yota Otachi , Manolis Vasilakis , Daniel Vaz

Motivated by the problem of routing reliably and scalably in a graph, we introduce the notion of a splicer, the union of spanning trees of a graph. We prove that for any bounded-degree n-vertex graph, the union of two random spanning trees…

Discrete Mathematics · Computer Science 2008-07-10 Navin Goyal , Luis Rademacher , Santosh Vempala

We study the problem of connecting the parts of a multipartite graph using a minimum number of edges under a matching constraint. We introduce interconnection trees, defined as matchings whose projections onto the quotient graph form a…

Computational Complexity · Computer Science 2026-05-19 Noé Demange , Yann Strozecki

A tessellation of a graph is a partition of its vertices into vertex disjoint cliques. A tessellation cover of a graph is a set of tessellations that covers all of its edges. The $t$-tessellability problem aims to decide whether there is a…

Discrete Mathematics · Computer Science 2021-06-24 A. Abreu , L. Cunha , T. Fernandes , C. de Figueiredo , L. Kowada , F. Marquezino , D. Posner , R. Portugal

Visual rendering of graphs is a key task in the mapping of complex network data. Although most graph drawing algorithms emphasize aesthetic appeal, certain applications such as travel-time maps place more importance on visualization of…

Machine Learning · Statistics 2014-01-20 Brian Baingana , Georgios B. Giannakis

A binary tanglegram is a pair <S,T> of binary trees whose leaf sets are in one-to-one correspondence; matching leaves are connected by inter-tree edges. For applications, for example in phylogenetics or software engineering, it is required…

Data Structures and Algorithms · Computer Science 2009-05-15 Martin Nöllenburg , Danny Holten , Markus Völker , Alexander Wolff

Grouping the nodes of a graph into clusters is a standard technique for studying networks. We study a problem where we are given a directed network and are asked to partition the graph into a sequence of coherent groups. We assume that…

Social and Information Networks · Computer Science 2025-12-08 Iiro Kumpulainen , Nikolaj Tatti

Let $k\ge 2$ be an integer and $T_1,\ldots, T_k$ be spanning trees of a graph $G$. If for any pair of vertices $(u,v)$ of $V(G)$, the paths from $u$ to $v$ in each $T_i$, $1\le i\le k$, do not contain common edges and common vertices,…

Discrete Mathematics · Computer Science 2014-09-23 Benoit Darties , Nicolas Gastineau , Olivier Togni

Bipartite graphs model the relationships between two disjoint sets of entities in several applications and are naturally drawn as 2-layer graph drawings. In such drawings, the two sets of entities (vertices) are placed on two parallel lines…

A temporal graph is a graph whose edges appear at certain points in time. These graphs are temporally connected (in class TC) if all vertices can reach each other by temporal paths (traversing the edges in chronological order). Reachability…

Discrete Mathematics · Computer Science 2026-04-21 Arnaud Casteigts , Timothée Corsini , Nils Morawietz

In the \textsc{Waypoint Routing Problem} one is given an undirected capacitated and weighted graph $G$, a source-destination pair $s,t\in V(G)$ and a set $W\subseteq V(G)$, of \emph{waypoints}. The task is to find a walk which starts at the…

Data Structures and Algorithms · Computer Science 2021-09-27 Šimon Schierreich , Ondřej Suchý

An effective way to reduce clutter in a graph drawing that has (many) crossings is to group edges that travel in parallel into \emph{bundles}. Each edge can participate in many such bundles. Any crossing in this bundled graph occurs between…

Computational Geometry · Computer Science 2022-09-23 Steven Chaplick , Thomas C. van Dijk , Myroslav Kryven , Ji-won Park , Alexander Ravsky , Alexander Wolff

In this paper, we revisit the problem of sampling edges in an unknown graph $G = (V, E)$ from a distribution that is (pointwise) almost uniform over $E$. We consider the case where there is some a priori upper bound on the arboriciy of $G$.…

Computational Complexity · Computer Science 2019-02-22 Talya Eden , Dana Ron , Will Rosenbaum

A tree $t$-spanner of a graph $G$ is a spanning tree of $G$ such that the distance between pairs of vertices in the tree is at most $t$ times their distance in $G$. Deciding tree $t$-spanner admissible graphs has been proved to be tractable…

Discrete Mathematics · Computer Science 2018-01-01 Ioannis Papoutsakis

Neural networks that compute over graph structures are a natural fit for problems in a variety of domains, including natural language (parse trees) and cheminformatics (molecular graphs). However, since the computation graph has a different…

Neural and Evolutionary Computing · Computer Science 2017-02-23 Moshe Looks , Marcello Herreshoff , DeLesley Hutchins , Peter Norvig

For an undirected tree with $n$ edges labelled by single letters, we consider its substrings, which are labels of the simple paths between pairs of nodes. We prove that there are $O(n^{1.5})$ different palindromic substrings. This solves an…

Data Structures and Algorithms · Computer Science 2020-11-30 Paweł Gawrychowski , Tomasz Kociumaka , Wojciech Rytter , Tomasz Waleń