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Related papers: Graphs with polynomially many minimal separators

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A graph is called (claw,diamond)-free if it contains neither a claw (a $K_{1,3}$) nor a diamond (a $K_4$ with an edge removed) as an induced subgraph. Equivalently, (claw,diamond)-free graphs can be characterized as line graphs of…

Data Structures and Algorithms · Computer Science 2015-03-03 Marek Cygan , Marcin Pilipczuk , Michał Pilipczuk , Erik Jan van Leeuwen , Marcin Wrochna

A Burling graph is an induced subgraph of some graph in Burling's construction of triangle-free high-chromatic graphs. Equivalently, a Burling graph is a graph that admits a so-called strict frame representation. We provide a…

Combinatorics · Mathematics 2026-04-28 Paweł Rzążewski , Bartosz Walczak

We present an algorithm that takes as input a graph $G$ with weights on the vertices, and computes a maximum weight independent set $S$ of $G$. If the input graph $G$ excludes a path $P_k$ on $k$ vertices as an induced subgraph, the…

Data Structures and Algorithms · Computer Science 2020-06-09 Peter Gartland , Daniel Lokshtanov

We design an $O(n^3)$ algorithm to find a minimum weighted coloring of a ($P_5, \bar{P}_5$)-free graph. Furthermore, the same technique can be used to solve the same problem for several classes of graphs, defined by forbidden induced…

Discrete Mathematics · Computer Science 2014-09-04 Chính T. Hoàng , D. Adam Lazzarato

We consider the class of (C4, diamond)-free graphs; graphs in this class do not contain a C4 or a diamond as an induced subgraph. We provide an efficient recognition algorithm for this class. We count the number of maximal cliques in a (C4,…

Discrete Mathematics · Computer Science 2009-09-28 Elaine M. Eschen , Chinh T. Hoang , Jeremy P. Spinrad , R. Sritharan

A minimal separator of a graph $G$ is a set $S \subseteq V(G)$ such that there exist vertices $a,b \in V(G) \setminus S$ with the property that $S$ separates $a$ from $b$ in $G$, but no proper subset of $S$ does. For an integer $k\ge 0$, we…

Combinatorics · Mathematics 2023-12-19 Martin Milanič , Irena Penev , Nevena Pivač , Kristina Vušković

For any finite set $\mathcal{H} = \{H_1,\ldots,H_p\}$ of graphs, a graph is $\mathcal{H}$-subgraph-free if it does not contain any of $H_1,\ldots,H_p$ as a subgraph. In recent work, meta-classifications have been studied: these show that if…

Data Structures and Algorithms · Computer Science 2023-05-03 Matthew Johnson , Barnaby Martin , Sukanya Pandey , Daniël Paulusma , Siani Smith , Erik Jan van Leeuwen

We prove that the Minimum Dominating Set problem is polynomial for the class of (claw, P8)-free graphs.

Combinatorics · Mathematics 2021-09-27 Valentin Bouquet , Christophe Picouleau

For an integer $t$, a graph $G$ is called {\em{$C_{>t}$-free}} if $G$ does not contain any induced cycle on more than~$t$ vertices. We prove the following statement: for every pair of integers $d$ and $t$ and a CMSO$_2$ statement~$\phi$,…

Data Structures and Algorithms · Computer Science 2021-01-13 Peter Gartland , Daniel Lokshtanov , Marcin Pilipczuk , Michal Pilipczuk , Pawel Rzazewski

We revisit a classical paper about (even hole, triangle)-free graphs [Conforti, Cornu\'ejols, Kapoor and Vu\v skovi\'c, Triangle-free graphs that are signable without even holes, Journal of Graph Theory, 34(3), 204--220, 2000]. In fact, the…

Combinatorics · Mathematics 2026-04-03 Beatriz Martins , Nicolas Trotignon

We study Steiner Forest on $H$-subgraph-free graphs, that is, graphs that do not contain some fixed graph $H$ as a (not necessarily induced) subgraph. We are motivated by a recent framework that completely characterizes the complexity of…

We study the problem of finding a maximum cardinality minimal separator of a graph. This problem is known to be NP-hard even for bipartite graphs. In this paper, we strengthen this hardness by showing that for planar bipartite graphs, the…

Data Structures and Algorithms · Computer Science 2020-09-28 Tesshu Hanaka , Yasuaki Kobayashi , Yusuke Kobayashi , Tsuyoshi Yagita

The Maximum Weight Independent Set (MWIS) problem on graphs with vertex weights asks for a set of pairwise nonadjacent vertices of maximum total weight. MWIS is known to be $NP$-complete in general, even under various restrictions. Let…

Discrete Mathematics · Computer Science 2016-03-16 T. Karthick

Sparse-dense partitions was introduced by Feder, Hell, Klein, and Motwani [STOC 1999, SIDMA 2003] as a tool to solve partitioning problems. In this paper, the following result concerning independent sets in graphs having sparse-dense…

Discrete Mathematics · Computer Science 2022-08-10 Uéverton S. Souza

Given a family $\mathcal{H}$ of graphs, we say that a graph $G$ is $\mathcal{H}$-free if no induced subgraph of $G$ is isomorphic to a member of $\mathcal{H}$. Let $S_{t,t,t}$ be the graph obtained from $K_{1,3}$ by subdividing each edge…

Combinatorics · Mathematics 2025-02-10 Maria Chudnovsky , Julien Codsi , Daniel Lokshtanov , Martin Milanič , Varun Sivashankar

The Maximum Weight Independent Set (MWIS) problem on finite undirected graphs with vertex weights asks for a set of pairwise nonadjacent vertices of maximum weight sum. MWIS is one of the most investigated and most important algorithmic…

Discrete Mathematics · Computer Science 2019-01-14 Andreas Brandstädt , Raffaele Mosca

We present a polynomial-time algorithm that determines whether a graph that contains no induced path on six vertices and no bull (the graph with vertices a, b, c, d, e and edges ab, bc, cd, be, ce) is 4-colorable. We also show that for any…

Combinatorics · Mathematics 2016-02-25 Frédéric Maffray , Lucas Pastor

Maximum Independent Set (MIS for short) is in general graphs the paradigmatic $W[1]$-hard problem. In stark contrast, polynomial-time algorithms are known when the inputs are restricted to structured graph classes such as, for instance,…

Data Structures and Algorithms · Computer Science 2019-09-19 Édouard Bonnet , Nicolas Bousquet , Stéphan Thomassé , Rémi Watrigant

Given a graph $G$, the maximal induced subgraphs problem asks to enumerate all maximal induced subgraphs of $G$ that belong to a certain hereditary graph class. While its optimization version, known as the minimum vertex deletion problem in…

Data Structures and Algorithms · Computer Science 2020-04-22 Yixin Cao

We study a conjecture due to Dallard, Krnc, Kwon, Milani\v{c}, Munaro, \v{S}torgel, and Wiederrecht stating that for any positive integer $d$ and any planar graph $H$, the class of all $K_{1,d}$-free graphs without $H$ as an induced minor…

Combinatorics · Mathematics 2025-06-11 Mujin Choi , Claire Hilaire , Martin Milanič , Sebastian Wiederrecht