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Optimal transport provides a metric which quantifies the dissimilarity between probability measures. For measures supported in discrete metric spaces, finding the optimal transport distance has cubic time complexity in the size of the…

Machine Learning · Computer Science 2024-01-30 Samantha Chen , Puoya Tabaghi , Yusu Wang

We give a series of new lower bounds on the minimum number of vertices required by a graph to contain every graph of a given family as induced subgraph. In particular, we show that this induced-universal graph for $n$-vertex planar graphs…

Combinatorics · Mathematics 2025-08-18 Cyril Gavoille , Amaury Jacques

The intersection graph of a collection of trapezoids with corner points lying on two parallel lines is called a trapezoid graph. Using binary indexed tree data structure, we improve algorithms for calculating the size and the number of…

Data Structures and Algorithms · Computer Science 2011-06-14 Aleksandar Ilic , Andreja Ilic

A tree t-spanner of an unweighted graph G is a spanning tree T such that for every two vertices their distance in T is at most t times their distance in G. Given an unweighted graph G and a positive integer t as input, the tree t-spanner…

Data Structures and Algorithms · Computer Science 2013-10-17 N. S. Narayanaswamy , G. Ramakrishna

We consider the NP-hard problem of finding a spanning tree with a maximum number of internal vertices. This problem is a generalization of the famous Hamiltonian Path problem. Our dynamic-programming algorithms for general and…

Data Structures and Algorithms · Computer Science 2009-06-12 Henning Fernau , Serge Gaspers , Daniel Raible

Embeddings of graphs into distributions of trees that preserve distances in expectation are a cornerstone of many optimization algorithms. Unfortunately, online or dynamic algorithms which use these embeddings seem inherently randomized and…

Data Structures and Algorithms · Computer Science 2021-02-11 Bernhard Haeupler , D Ellis Hershkowitz , Goran Zuzic

Given an $n$-vertex non-negatively real-weighted graph $G$, whose vertices are partitioned into a set of $k$ clusters, a \emph{clustered network design problem} on $G$ consists of solving a given network design optimization problem on $G$,…

Data Structures and Algorithms · Computer Science 2018-02-01 Mattia D'Emidio , Luca Forlizzi , Daniele Frigioni , Stefano Leucci , Guido Proietti

We study the problem of how well a tree metric is able to preserve the sum of pairwise distances of an arbitrary metric. This problem is closely related to low-stretch metric embeddings and is interesting by its own flavor from the line of…

Data Structures and Algorithms · Computer Science 2013-01-16 Mong-Jen Kao , Der-Tsai Lee , Dorothea Wagner

An added edge to a graph is called an inset edge. Predicting k inset edges which minimize the average distance of a graph is known to be NP-Hard. When k = 1 the complexity of the problem is polynomial. In this paper, we further find the…

Data Structures and Algorithms · Computer Science 2020-08-14 M. H. Khalifeh , A. -H. Esfahanian

Tree rotations (left and right) are basic local deformations allowing to transform between two unlabeled binary trees of the same size. Hence, there is a natural problem of practically finding such transformation path with low number of…

Data Structures and Algorithms · Computer Science 2016-10-20 Jarek Duda

The Subtree Isomorphism problem asks whether a given tree is contained in another given tree. The problem is of fundamental importance and has been studied since the 1960s. For some variants, e.g., ordered trees, near-linear time algorithms…

Computational Complexity · Computer Science 2015-10-16 Amir Abboud , Arturs Backurs , Thomas Dueholm Hansen , Virginia Vassilevska Williams , Or Zamir

A classical result of Koml\'os, S\'ark\"ozy and Szemer\'edi states that every $n$-vertex graph with minimum degree at least $(1/2+ o(1))n$ contains every $n$-vertex tree with maximum degree $O(n/\log{n})$ as a subgraph, and the bounds on…

Combinatorics · Mathematics 2018-03-14 Felix Joos , Jaehoon Kim

We prove that every oriented tree on $n$ vertices with bounded maximum degree appears as a spanning subdigraph of every directed graph on $n$ vertices with minimum semidegree at least $n/2+o(n)$. This can be seen as a directed graph…

Combinatorics · Mathematics 2026-05-20 Richard Mycroft , Tássio Naia

We present two new and efficient algorithms for computing all-pairs shortest paths. The algorithms operate on directed graphs with real (possibly negative) weights. They make use of directed path consistency along a vertex ordering d. Both…

Data Structures and Algorithms · Computer Science 2014-01-21 Léon R. Planken , Mathijs M. de Weerdt , Roman P. J. van der Krogt

An independent edge set of graph $G$ is a matching, and is maximal if it is not a proper subset of any other matching of $G$. The number of all the maximal matchings of $G$ is denoted by $\Psi(G)$. In this paper, an algorithm to count…

Combinatorics · Mathematics 2025-06-11 Lingjuan Shi , Wei Li , Kai Deng

A "tree-partition" of a graph $G$ is a partition of $V(G)$ such that identifying the vertices in each part gives a tree. It is known that every graph with treewidth $k$ and maximum degree $\Delta$ has a tree-partition with parts of size…

Combinatorics · Mathematics 2023-07-31 Marc Distel , David R. Wood

Let $H$ be a fixed graph and let $G$ be an $H$-minor free $n$-vertex graph with integer edge weights and no negative weight cycles reachable from a given vertex $s$. We present an algorithm that computes a shortest path tree in $G$ rooted…

Discrete Mathematics · Computer Science 2010-10-12 Christian Wulff-Nilsen

An isometric path between two vertices in a graph G is a shortest path joining them. The isometric-path number of G, denoted by ip(G), is the minimum number of isometric paths required to cover all vertices of G. In this paper, we determine…

Combinatorics · Mathematics 2007-05-23 Jun-Jie Pand , Gerard J. Chang

We present the first near-linear work and poly-logarithmic depth algorithm for computing a minimum cut in a graph, while previous parallel algorithms with poly-logarithmic depth required at least quadratic work in the number of vertices. In…

Distributed, Parallel, and Cluster Computing · Computer Science 2020-07-03 Barbara Geissmann , Lukas Gianinazzi

In the PATH COVER problem, one asks to cover the vertices of a graph using the smallest possible number of (not necessarily disjoint) paths. While the variant where the paths need to be pairwise vertex-disjoint, which we call PATH…

Data Structures and Algorithms · Computer Science 2025-11-11 Florent Foucaud , Atrayee Majumder , Tobias Mömke , Aida Roshany-Tabrizi