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The $c$-packedness property, proposed in 2010, is a geometric property that captures the spatial distribution of a set of edges. Despite the recent interest in $c$-packedness, its utility has so far been limited to Fr\'echet distance…

Computational Geometry · Computer Science 2025-05-13 Lindsey Deryckere , Joachim Gudmundsson , André van Renssen , Yuan Sha , Sampson Wong

We prove that Graph Isomorphism and Canonization in graphs excluding a fixed graph $H$ as a minor can be solved by an algorithm working in time $f(H)\cdot n^{O(1)}$, where $f$ is some function. In other words, we show that these problems…

Data Structures and Algorithms · Computer Science 2022-10-27 Daniel Lokshtanov , Marcin Pilipczuk , Michał Pilipczuk , Saket Saurabh

We give a fixed-parameter tractable algorithm that, given a parameter $k$ and two graphs $G_1,G_2$, either concludes that one of these graphs has treewidth at least $k$, or determines whether $G_1$ and $G_2$ are isomorphic. The running time…

Data Structures and Algorithms · Computer Science 2014-12-11 Daniel Lokshtanov , Marcin Pilipczuk , Michał Pilipczuk , Saket Saurabh

We introduce the graph theoretical parameter of edge treewidth. This parameter occurs in a natural way as the tree-like analogue of cutwidth or, alternatively, as an edge-analogue of treewidth. We study the combinatorial properties of…

Discrete Mathematics · Computer Science 2021-12-15 Loïc Magne , Christophe Paul , Abhijat Sharma , Dimitrios M. Thilikos

Percolation theory can be used to describe the structural properties of complex networks using the generating function formulation. This mapping assumes that the network is locally tree-like and does not contain short-range loops between…

Physics and Society · Physics 2021-02-03 Peter Mann , V. Anne Smith , John B. O. Mitchell , Simon Dobson

This is the second of a series of four papers in which we prove the following relaxation of the Loebl-Komlos--Sos Conjecture: For every $\alpha>0$ there exists a number $k_0$ such that for every $k>k_0$ every $n$-vertex graph $G$ with at…

Combinatorics · Mathematics 2017-07-31 Jan Hladký , János Komlós , Diana Piguet , Miklós Simonovits , Maya J. Stein , Endre Szemerédi

We show an algorithm that, given an $n$-vertex graph $G$ and a parameter $k$, in time $2^{O(k \log k)} n^{O(1)}$ finds a tree decomposition of $G$ with the following properties: * every adhesion of the tree decomposition is of size at most…

Data Structures and Algorithms · Computer Science 2020-09-29 Marek Cygan , Paweł Komosa , Daniel Lokshtanov , Michał Pilipczuk , Marcin Pilipczuk , Saket Saurabh , Magnus Wahlström

Twin-width is a structural width parameter introduced by Bonnet, Kim, Thomass\'e and Watrigant [FOCS 2020]. Very briefly, its essence is a gradual reduction (a contraction sequence) of the given graph down to a single vertex while…

Mubayi and Verstraete conjectured that if $T$ is a tree on $t + 1$ vertices, then any $n$-vertex graph $G$ with average degree $d$ contains at least \[ n d(d - 1) \cdots (d - t + 1) \] labeled copies of $T$ as long as $d$ is sufficiently…

Combinatorics · Mathematics 2025-12-18 Chase Wilson

Temporal graphs are graphs whose edges are only present at certain points in time. Reachability in these graphs relies on temporal paths, where edges are traversed chronologically. A temporal graph that offers all-pairs reachability is said…

Computational Complexity · Computer Science 2026-04-28 Arnaud Casteigts , Christian Komusiewicz , Nils Morawietz

Graph decompositions are the natural generalisation of tree decompositions where the decomposition tree is replaced by a genuine graph. Recently they found theoretical applications in the theory of sparsity, topological graph theory,…

Discrete Mathematics · Computer Science 2023-12-20 Johannes Carmesin , Sarah Frenkel

For a graph $G$, the tree graph ${\cal T}_{G,t}$ has all tree subgraphs of $G$ with $t$ vertices as vertex set and two tree subgraphs are neighbors if they are edge-disjoint. Also, the $r^{th}$ cut number of $G$ is the minimum number of…

Combinatorics · Mathematics 2015-12-01 Meysam Alishahi , Hossein Hajiabolhassan

Let $G=(V,E)$ be a finite, combinatorial graph. We define a notion of curvature on the vertices $V$ via the inverse of the resistance distance matrix. We prove that this notion of curvature has a number of desirable properties. Graphs with…

Combinatorics · Mathematics 2023-02-22 Karel Devriendt , Andrea Ottolini , Stefan Steinerberger

We show that every connected graph $G$ has a tree decomposition indexed by a tree $T$ such that $T$ is a subgraph of $G$ and the width of the tree decomposition is bounded from above by a function of the pathwidth of $G$. This answers a…

Combinatorics · Mathematics 2026-03-02 Romain Bourneuf , Gwenaël Joret , Piotr Micek , Martin Milanič , Michał Pilipczuk

Large graphs are sometimes studied through their degree sequences (power law or regular graphs). We study graphs that are uniformly chosen with a given degree sequence. Under mild conditions, it is shown that sequences of such graphs have…

Probability · Mathematics 2011-08-31 Sourav Chatterjee , Persi Diaconis , Allan Sly

An ordered graph is a graph enhanced with a linear order on the vertex set. An ordered graph is a core if it does not have an order-preserving homomorphism to a proper subgraph. We say that $H$ is the core of $G$ if (i) $H$ is a core, (ii)…

Computational Complexity · Computer Science 2025-12-01 Michal Čertík , Andreas Emil Feldmann , Jaroslav Nešetřil , Paweł Rzążewski

Given a graph property $\mathcal{P}$, it is interesting to determine the typical structure of graphs that satisfy $\mathcal{P}$. In this paper, we consider monotone properties, that is, properties that are closed under taking subgraphs.…

Combinatorics · Mathematics 2014-04-10 Svante Janson , Andrew J. Uzzell

We show that graphs generated by collapsible pushdown systems of level 2 are tree-automatic. Even if we allow epsilon-contractions and reachability predicates (with regular constraints) for pairs of configurations, the structures remain…

Logic in Computer Science · Computer Science 2015-07-01 Alexander Kartzow

We show that a locally finite, connected graph $G$ is $r$-locally chordal (that is, its $r/2$-balls are chordal) if and only if the unique canonical graph-decomposition $\mathcal{H}_r(G)$ of $G$ displaying its $r$-global structure is into…

Combinatorics · Mathematics 2026-05-05 Raphael W. Jacobs , Paul Knappe

Given a graph $G$ rooted at a vertex $r$ and weight functions, $\gamma, \tau: E(G) \rightarrow \mathbb{R}$, the generalized cable-trench problem (CTP) is to find a single spanning tree that simultaneously minimizes the sum of the total edge…

Combinatorics · Mathematics 2025-02-12 Mya Davis , Carl Hammarsten , Siddarth Menon , Maria Pasaylo , Dane Sheridan
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