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Related papers: Maximum independent sets in (pyramid, even hole)-f…

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A {\em hole} is a chordless cycle of length at least four. A hole is {\em even} (resp. {\em odd}) if it contains an even (resp. odd) number of vertices. A \emph{cap} is a graph induced by a hole with an additional vertex that is adjacent to…

Discrete Mathematics · Computer Science 2015-11-02 Shenwei Huang , Murilo V. G. da Silva

We give a combinatorial polynomial-time algorithm to find a maximum weight independent set in perfect graphs of bounded degree that do not contain a prism or a hole of length four as an induced subgraph. An even pair in a graph is a pair of…

Combinatorics · Mathematics 2024-01-09 Tara Abrishami , Maria Chudnovsky , Cemil Dibek , Kristina Vušković

A \emph{hole} is a chordless cycle of length at least $4$. A graph is \emph{even-hole-free} if it does not contain any hole of even length as an induced subgraph. In this paper, we study the class of even-hole-free graphs with no star…

Discrete Mathematics · Computer Science 2018-06-08 Ngoc Khang Le

We show that graphs that do not contain a theta, pyramid, prism, or turtle as an induced subgraph have polynomially many minimal separators. This result is the best possible in the sense that there are graphs with exponentially many minimal…

A {\em theta} is a graph made of three internally vertex-disjoint chordless paths $P_1 = a \dots b$, $P_2 = a \dots b$, $P_3 = a \dots b$ of length at least~2 and such that no edges exist between the paths except the three edges incident to…

Discrete Mathematics · Computer Science 2023-10-23 Marcin Pilipczuk , Ni Luh Dewi Sintiari , Stéphan Thomassé , Nicolas Trotignon

A hole in a graph is an induced cycle of length at least $4$, and an antihole is the complement of an induced cycle of length at least $4$. A hole or antihole is long if its length is at least $5$. For an integer $k$, the $k$-prism is the…

Discrete Mathematics · Computer Science 2020-01-17 Maria Chudnovsky , Marcin Pilipczuk , Michał Pilipczuk , Stéphan Thomassé

The class of even-hole-free graphs is very similar to the class of perfect graphs, and was indeed a cornerstone in the tools leading to the proof of the Strong Perfect Graph Theorem. However, the complexity of computing a maximum…

Combinatorics · Mathematics 2019-10-08 Edin Husic , Stephan Thomasse , Nicolas Trotignon

A hole in a graph is an induced cycle of length at least 4. A hole is long if its length is at least 5. By $P_t$ we denote a path on $t$ vertices. In this paper we give polynomial-time algorithms for the following problems: the Maximum…

Data Structures and Algorithms · Computer Science 2020-03-12 Tara Abrishami , Maria Chudnovsky , Marcin Pilipczuk , Paweł Rzążewski , Paul Seymour

A hole in a graph $G$ is an induced cycle of length at least four, and an even hole is a hole of even length. The diamond is the graph obtained from the complete graph $K_4$ by removing an edge. A pyramid is a graph consisting of a triangle…

Combinatorics · Mathematics 2023-09-06 Tara Abrishami , Maria Chudnovsky , Sepehr Hajebi , Sophie Spirkl

A {\em hole} in a graph is an induced subgraph which is a cycle of length at least four. A hole is called {\em even} if it has an even number of vertices. An {\em even-hole-free} graph is a graph with no even holes. A vertex of a graph is…

Combinatorics · Mathematics 2020-05-18 Maria Chudnovsky , Paul Seymour

A \emph{wheel} is a graph formed by a chordless cycle $C$ and a vertex $u$ not in $C$ that has at least three neighbors in $C$. We prove that every 3-connected planar graph that does not contain a wheel as an induced subgraph is either a…

Combinatorics · Mathematics 2015-04-09 Pierre Aboulker , Maria Chudnovsky , Paul Seymour , Nicolas Trotignon

A hole in a graph is a chordless cycle of length at least 4. A theta is a graph formed by three paths between the same pair of distinct vertices so that the union of any two of the paths induces a hole. A wheel is a graph formed by a hole…

Combinatorics · Mathematics 2023-10-23 Marko Radovanović , Nicolas Trotignon , Kristina Vušković

A hole in a graph is a chordless cycle of length at least 4. A theta is a graph formed by three internally vertex-disjoint paths of length at least 2 between the same pair of distinct vertices. A wheel is a graph formed by a hole and a node…

Combinatorics · Mathematics 2023-10-23 Marko Radovanović , Nicolas Trotignon , Kristina Vušković

A graph is even-hole-free if it has no induced even cycles of length 4 or more. A cap is a cycle of length at least 5 with exactly one chord and that chord creates a triangle with the cycle. In this paper, we consider (cap, even hole)-free…

Discrete Mathematics · Computer Science 2016-11-28 Kathie Cameron , Murilo V. G. da Silva , Shenwei Huang , Kristina Vušković

In the classic Maximum Weight Independent Set problem we are given a graph $G$ with a nonnegative weight function on vertices, and the goal is to find an independent set in $G$ of maximum possible weight. While the problem is NP-hard in…

Data Structures and Algorithms · Computer Science 2020-03-24 Andrzej Grzesik , Tereza Klimošová , Marcin Pilipczuk , Michał Pilipczuk

We prove that the tree independence number of every even-hole-free graph is at most polylogarithmic in its number of vertices. More explicitly, we prove that there exists a constant c>0 such that for every integer n>1 every n-vertex…

Combinatorics · Mathematics 2024-07-15 Maria Chudnovsky , Peter Gartland , Sepehr Hajebi , Daniel Lokshtanov , Sophie Spirkl

An even hole is an induced chordless cycle of even length at least four. A diamond is an induced subgraph isomorphic to K_4-e. We show that graphs without even holes and without diamonds can be decomposed via clique-separators into graphs…

Combinatorics · Mathematics 2011-04-21 Ton Kloks

A \emph{unichord} in a graph is an edge that is the unique chord of a cycle. A \emph{square} is an induced cycle on four vertices. A graph is \emph{unichord-free} if none of its edges is a unichord. We give a slight restatement of a known…

Discrete Mathematics · Computer Science 2014-02-05 Raphael C. S. Machado , Celina M. H. de Figueiredo , Nicolas Trotignon

We consider the class of graphs containing no odd hole, no odd antihole, and no configuration consisting of three paths between two nodes such that any two of the paths induce a hole, and at least two of the paths are of length 2. This…

Discrete Mathematics · Computer Science 2016-03-27 Frédéric Maffray , Nicolas Trotignon , Kristina Vušković

A three-path-configuration is a graph consisting of three pairwise internally-disjoint paths the union of every two of which is an induced cycle of length at least four. A graph is 3PC-free if no induced subgraph of it is a…

Combinatorics · Mathematics 2025-11-14 Maria Chudnovsky , Sepehr Hajebi , Daniel Lokshtanov , Sophie Spirkl
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