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We develop a structural approach to simultaneous embeddability in temporal sequences of graphs, inspired by graph minor theory. Our main result is a classification theorem for 2-connected temporal sequences: we identify five obstruction…

Combinatorics · Mathematics 2025-04-02 Johannes Carmesin , Will J. Turner

We give the first polynomial-time algorithms on graphs of bounded maximum induced matching width (mim-width) for problems that are not locally checkable. In particular, we give $n^{\mathcal{O}(w)}$-time algorithms on graphs of mim-width at…

Data Structures and Algorithms · Computer Science 2017-09-29 Lars Jaffke , O-joung Kwon , Jan Arne Telle

An oriented k-uniform hypergraph (a family of ordered k-sets) has the ordering property (or Property O) if for every linear order of the vertex set, there is some edge oriented consistently with the linear order. We find bounds on the…

Combinatorics · Mathematics 2016-08-24 Dwight Duffus , Bill Kay , Vojtech Rodl

We prove the following theorem. Given a planar graph $G$ and an integer $k$, it is possible in polynomial time to randomly sample a subset $A$ of vertices of $G$ with the following properties: (i) $A$ induces a subgraph of $G$ of treewidth…

Data Structures and Algorithms · Computer Science 2016-04-21 Fedor V. Fomin , Daniel Lokshtanov , Dániel Marx , Marcin Pilipczuk , Michał Pilipczuk , Saket Saurabh

A graph $H$ is an induced subgraph of a graph $G$ if a graph isomorphic to $H$ can be obtained from $G$ by deleting vertices. Recently, there has been significant interest in understanding the unavoidable induced subgraphs for graphs of…

Combinatorics · Mathematics 2022-07-01 Robert Hickingbotham

In a graph $G$, a vertex subset $S\subseteq V(G)$ is said to be a dominating set of $G$ if every vertex not in $S$ is adjacent to a vertex in $S$. A dominating set $S$ of a graph $G$ is called a paired-dominating set if the induced subgraph…

Data Structures and Algorithms · Computer Science 2014-01-30 Ching-Chi Lin , Hai-Lun Tu

We show that the left/right relation on the set of s-t-paths of a plane graph induces a so-called submodular lattice. If the embedding of the graph is s-t-planar, this lattice is even consecutive. This implies that Ford and Fulkerson's…

Discrete Mathematics · Computer Science 2012-11-12 Jannik Matuschke , Britta Peis

A linear inference is a valid inequality of Boolean algebra in which each variable occurs at most once on each side. In this work we leverage recently developed graphical representations of linear formulae to build an implementation that is…

Logic in Computer Science · Computer Science 2024-02-14 Anupam Das , Alex Rice

A graph $G$ contains a graph $H$ as an induced minor if $H$ can be obtained from $G$ by vertex deletions and edge contractions. The class of $H$-induced-minor-free graphs generalizes the class of $H$-minor-free graphs, but unlike…

Data Structures and Algorithms · Computer Science 2023-08-10 Tuukka Korhonen , Daniel Lokshtanov

In this paper we analyze a variant of the pursuit-evasion game on a graph $G$ where the intruder occupies a vertex, is allowed to move to adjacent vertices or remain in place, and is 'invisible' to the searcher, meaning that the searcher…

Combinatorics · Mathematics 2022-04-07 Anton Bernshteyn , Eugene Lee

A graph $H$ is said to be an induced minor of a graph $G$ if $H$ can be obtained from $G$ by a sequence of vertex deletions and edge contractions. Equivalently, $H$ is an induced minor of $G$ if there exists an induced minor model of $H$ in…

The recently introduced problem of extending partial interval representations asks, for an interval graph with some intervals pre-drawn by the input, whether the partial representation can be extended to a representation of the entire…

Discrete Mathematics · Computer Science 2014-08-26 Pavel Klavík , Jan Kratochvíl , Yota Otachi , Ignaz Rutter , Toshiki Saitoh , Maria Saumell , Tomáš Vyskočil

We consider the graph class Grounded-L corresponding to graphs that admit an intersection representation by L-shaped curves, where additionally the topmost points of each curve are assumed to belong to a common horizontal line. We prove…

Combinatorics · Mathematics 2019-11-06 Vít Jelínek , Martin Töpfer

Let $B$ be a set of Eulerian subgraphs of a graph $G$. We say $B$ forms a $k$-basis if it is a minimum set that generates the cycle space of $G$, and any edge of $G$ lies in at most $k$ members of $B$. The basis number of a graph $G$,…

Combinatorics · Mathematics 2024-12-25 Saman Bazargani , Therese Biedl , Prosenjit Bose , Anil Maheshwari , Babak Miraftab

Word-representable graphs, characterized by the existence of a semi-transitive orientation, form a well-studied class of graphs. Comparability graphs form another well-studied class and constitute a subclass of word-representable graphs.…

Discrete Mathematics · Computer Science 2026-05-15 Benny George Kenkireth , Gopalan Sajith , Sreyas Sasidharan

We shall present an algorithm for determining whether or not a given planar graph H can ever be a subgraph of a 4-regular planar graph. The algorithm has running time O(|H|^{2.5}) and can be used to find an explicit 4-regular planar graph G…

Combinatorics · Mathematics 2013-07-23 Chris Dowden , Louigi Addario-Berry

A cocomparability graph is a graph whose complement admits a transitive orientation. An interval graph is the intersection graph of a family of intervals on the real line. In this paper we investigate the relationships between interval and…

Discrete Mathematics · Computer Science 2016-11-08 Jérémie Dusart , Michel Habib , Derek G. Corneil

A graph $G$ is said to be an $(s, k)$-polar graph if its vertex set admits a partition $(A, B)$ such that $A$ and $B$ induce, respectively, a complete $s$-partite graph and the disjoint union of at most $k$ complete graphs. Polar graphs and…

Combinatorics · Mathematics 2024-10-16 Fernando Esteban Contreras-Mendoza , César Hernández-Cruz

We present the first parallel fixed-parameter algorithm for subgraph isomorphism in planar graphs, bounded-genus graphs, and, more generally, all minor-closed graphs of locally bounded treewidth. Our randomized low depth algorithm has a…

Data Structures and Algorithms · Computer Science 2020-07-03 Lukas Gianinazzi , Torsten Hoefler

We discuss some problems related to induced subgraphs. The first problem is about getting a good upper bound for the chromatic number in terms of the clique number for graphs in which every induced cycle has length $3$ or $4$. The second…

Combinatorics · Mathematics 2018-01-08 Vaidy Sivaraman