English
Related papers

Related papers: Graphs with polynomially many minimal separators

200 papers

We revisit the recent polynomial-time algorithm for the MAX WEIGHT INDEPENDENT SET (MWIS) problem in bounded-degree graphs that do not contain a fixed graph whose every component is a subdivided claw as an induced subgraph [Abrishami,…

Data Structures and Algorithms · Computer Science 2024-01-15 Tara Abrishami , Maria Chudnovsky , Cemil Dibek , Marcin Pilipczuk , Paweł Rzążewski

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 $W_{t\times t}$ be the $t$-by-$t$ hexagonal grid and let $\mathcal{L}_t$ be…

Combinatorics · Mathematics 2025-09-22 Maria Chudnovsky , Julien Codsi

Potential maximal cliques and minimal separators are combinatorial objects which were introduced and studied in the realm of minimal triangulations problems including Minimum Fill-in and Treewidth. We discover unexpected applications of…

Data Structures and Algorithms · Computer Science 2009-12-22 Fedor V. Fomin , Yngve Villanger

A connected graph is 2K2-free if it does not contain a pair of independent edges as an induced subgraph. In this paper, we present the structural characterization of minimal vertex separator and show that there are polynomial number of…

Combinatorics · Mathematics 2016-03-30 S. Dhanalakshmi , N. Sadagopan , V. Manogna

We show that the Maximum Weight Independent Set problem (MWIS) can be solved in quasi-polynomial time on $H$-free graphs (graphs excluding a fixed graph $H$ as an induced subgraph) for every $H$ whose every connected component is a path or…

Data Structures and Algorithms · Computer Science 2025-09-24 Peter Gartland , Daniel Lokshtanov , Tomáš Masařík , Marcin Pilipczuk , Michał Pilipczuk , Paweł Rzążewski

The maximum stable set problem is NP-hard, even when restricted to triangle-free graphs. In particular, one cannot expect a polynomial time algorithm deciding if a bull-free graph has a stable set of size $k$, when $k$ is part of the…

Discrete Mathematics · Computer Science 2015-11-20 Stéphan Thomassé , Nicolas Trotignon , Kristina Vusković

We revisit recent developments for the Maximum Weight Independent Set problem in graphs excluding a subdivided claw $S_{t,t,t}$ as an induced subgraph [Chudnovsky, Pilipczuk, Pilipczuk, Thomass\'{e}, SODA 2020] and provide a…

Data Structures and Algorithms · Computer Science 2026-02-19 Konrad Majewski , Tomáš Masařík , Jana Novotná , Karolina Okrasa , Marcin Pilipczuk , Paweł Rzążewski , Marek Sokołowski

The independence number of a tree decomposition is the size of a largest independent set contained in a single bag. The tree-independence number of a graph $G$ is the minimum independence number of a tree decomposition of $G$. As shown…

Data Structures and Algorithms · Computer Science 2026-01-23 Daniel Lokshtanov , Michał Pilipczuk , Paweł Rzążewski

The celebrated notion of important separators bounds the number of small $(S,T)$-separators in a graph which are 'farthest from $S$' in a technical sense. In this paper, we introduce a generalization of this powerful algorithmic primitive…

Data Structures and Algorithms · Computer Science 2023-09-21 Bart M. P. Jansen , Jari J. H. de Kroon , Michał Włodarczyk

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

This paper is motivated by the following question: what are the unavoidable induced subgraphs of graphs with large treewidth? Aboulker et al. made a conjecture which answers this question in graphs of bounded maximum degree, asserting that…

We present a quasipolynomial-time approximation scheme (QPTAS) for the Maximum Independent Set (\textsc{MWIS}) in graphs with a bounded number of pairwise vertex-disjoint and non-adjacent long induced cycles. More formally, for every fixed…

Data Structures and Algorithms · Computer Science 2026-02-23 Édouard Bonnet , Jadwiga Czyżewska , Tomáš Masařík , Marcin Pilipczuk , Paweł Rzążewski

In a recent breakthrough work, Gartland and Lokshtanov [FOCS 2020] showed a quasi-polynomial-time algorithm for Maximum Weight Independent Set in $P_t$-free graphs, that is, graphs excluding a fixed path as an induced subgraph. Their…

Data Structures and Algorithms · Computer Science 2020-11-18 Marcin Pilipczuk , Michał Pilipczuk , Paweł Rzążewski

We recall several known results about minimally 2-connected graphs, and show that they all follow from a decomposition theorem. Starting from an analogy with critically 2-connected graphs, we give structural characterizations of the classes…

Discrete Mathematics · Computer Science 2016-03-27 Pierre Aboulker , Marko Radovanović , Nicolas Trotignon , Kristina Vušković

We continue the study of graph classes in which the treewidth can only be large due to the presence of a large clique, and, more specifically, of graph classes with bounded tree-independence number. In [Dallard, Milani\v{c}, and…

Data Structures and Algorithms · Computer Science 2022-09-27 Martin Milanič , Paweł Rzążewski

In this paper, we show the existence of a polynomial time graph isomorphism algorithm for all graphs excluding graphs that are locally trianglefree. This particular class of graphs allows to divide the graph into neighbourhood sub-graph…

Data Structures and Algorithms · Computer Science 2016-06-02 Fahad Bin Mortuza

In the Maximum Independent Set problem we are asked to find a set of pairwise nonadjacent vertices in a given graph with the maximum possible cardinality. In general graphs, this classical problem is known to be NP-hard and hard to…

Data Structures and Algorithms · Computer Science 2023-11-15 Maria Chudnovsky , Marcin Pilipczuk , Michał Pilipczuk , Stéphan Thomassé

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

The problem of determining the maximum number of maximal independent sets in certain graph classes dates back to a paper of Miller and Muller and a question of Erd\H{o}s and Moser from the 1960s. The minimum was always considered to be less…

Combinatorics · Mathematics 2024-09-17 Stijn Cambie , Stephan Wagner

For graphs $G$ and $H$, we say that $G$ is $H$-free if it does not contain $H$ as an induced subgraph. Already in the early 1980s Alekseev observed that if $H$ is connected, then the \textsc{Max Weight Independent Set} problem (MWIS)…

Data Structures and Algorithms · Computer Science 2022-02-09 Tara Abrishami , Maria Chudnovsky , Cemil Dibek , Paweł Rzążewski