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Related papers: Induced forests in regular graphs with large girth

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The induced arboricity of a graph $G$ is the smallest number of induced forests covering the edges of $G$. This is a well-defined parameter bounded from above by the number of edges of $G$ when each forest in a cover consists of exactly one…

Combinatorics · Mathematics 2017-06-01 Maria Axenovich , Daniel Goncalves , Jonathan Rollin , Torsten Ueckerdt

In this paper, we address the maximum number of vertices of induced forests in subcubic graphs with girth at least four or five. We provide a unified approach to prove that every 2-connected subcubic graph on $n$ vertices and $m$ edges with…

Combinatorics · Mathematics 2022-12-06 Tom Kelly , Chun-Hung Liu

For a graph $G$, let $a(G)$ denote the maximum size of a subset of vertices that induces a forest. We prove the following. 1. Let $G$ be a graph of order $n$, maximum degree $\Delta>0$ and maximum clique size $\omega$. Then \[ a(G) \geq…

Combinatorics · Mathematics 2019-10-04 Shimon Kogan

In this article, we study the order and structure of the largest induced forests in some families of graphs. First we prove a variation of the ratio bound that gives an upper bound on the order of the largest induced forest in a graph. Next…

Combinatorics · Mathematics 2024-04-17 Karen Gunderson , Karen Meagher , Joy Morris , Venkata Raghu Tej Pantangi

Asymptotic behaviour of maximum sizes of induced trees and forests has been studied extensively in last decades, though the overall picture is far from being complete. In this paper, we close several significant gaps: 1) We prove $2$-point…

Combinatorics · Mathematics 2024-08-28 Margarita Akhmejanova , Vladislav Kozhevnikov , Maksim Zhukovskii

In this paper we show how to find nearly optimal embeddings of large trees in several natural classes of graphs. The size of the tree T can be as large as a constant fraction of the size of the graph G, and the maximum degree of T can be…

Combinatorics · Mathematics 2007-07-17 Benny Sudakov , Jan Vondrak

We give here some new lower bounds on the order of a largest induced forest in planar graphs with girth $4$ and $5$. In particular we prove that a triangle-free planar graph of order $n$ admits an induced forest of order at least…

Discrete Mathematics · Computer Science 2014-09-05 François Dross , Mickael Montassier , Alexandre Pinlou

We prove that for all $0\leq t\leq k$ and $d\geq 2k$, every graph $G$ with treewidth at most $k$ has a `large' induced subgraph $H$, where $H$ has treewidth at most $t$ and every vertex in $H$ has degree at most $d$ in $G$. The order of $H$…

Combinatorics · Mathematics 2007-05-23 Prosenjit Bose , Vida Dujmovic , David R. Wood

A well-known result due to Caro (1979) and Wei (1981) states that every graph $G$ has an independent set of size at least $\sum_{v\in V(G)} \frac{1}{d(v) + 1}$, where $d(v)$ denotes the degree of vertex $v$. Alon, Kahn, and Seymour (1987)…

Combinatorics · Mathematics 2025-08-11 Gwenaël Joret , Robin Petit

An equitable partition of a graph $G$ is a partition of the vertex-set of $G$ such that the sizes of any two parts differ by at most one. We show that every graph with an acyclic coloring with at most $k$ colors can be equitably partitioned…

Combinatorics · Mathematics 2015-04-17 Louis Esperet , Laetitia Lemoine , Frédéric Maffray

We show that for any fixed dense graph G and bounded-degree tree T on the same number of vertices, a modest random perturbation of G will typically contain a copy of T . This combines the viewpoints of the well-studied problems of embedding…

Combinatorics · Mathematics 2025-05-30 Michael Krivelevich , Matthew Kwan , Benny Sudakov

In this paper, a new concept in graphs namely well-f-coveredness is introduced. We characterize all graphs with such property, whose maximum induced forests are of boundary order. Also we prove several propositions concerning with obtaining…

Combinatorics · Mathematics 2021-06-01 Reza Jafarpour-Golzari

Graph isomorphism, subgraph isomorphism, and maximum common subgraphs are classical well-investigated objects. Their (parameterized) complexity and efficiently tractable cases have been studied. In the present paper, for a given set of…

Data Structures and Algorithms · Computer Science 2024-03-22 Dieter Rautenbach , Florian Werner

Albertson and Berman conjectured that every planar graph has an induced forest on half of its vertices. The best known lower bound, due to Borodin, is that every planar graph has an induced forest on two fifths of its vertices. In a related…

Combinatorics · Mathematics 2026-03-19 Glencora Borradaile , Hung Le , Melissa Sherman-Bennett

Let $F(G)$ be the number of forests of a graph $G$. Similarly let $C(G)$ be the number of connected spanning subgraphs of a connected graph $G$. We bound $F(G)$ and $C(G)$ for regular graphs and for graphs with fixed average degree. Among…

Combinatorics · Mathematics 2021-08-03 Márton Borbényi , Péter Csikvári , Haoran Luo

We show that there exists a graph $G$ with $O(n)$ nodes, where any forest of $n$ nodes is a node-induced subgraph of $G$. Furthermore, for constant arboricity $k$, the result implies the existence of a graph with $O(n^k)$ nodes that…

Data Structures and Algorithms · Computer Science 2016-02-17 Stephen Alstrup , Søren Dahlgaard , Mathias Bæk Tejs Knudsen

The avoidance of induced forests, or induced acyclic subgraphs, in $d$-dimensional grid graphs, or lattice graphs, has been studied in Alon et al. and later in Caragiannis et al., finding upper and lower bounds with respect to the number of…

Combinatorics · Mathematics 2026-05-27 Taiki Aiba , Ernie Croot

In the Fully Leafed Induced Subtrees, one is given a graph $G$ and two integers $a$ and $b$ and the question is to find an induced subtree of $G$ with $a$ vertices and at least $b$ leaves. This problem is known to be NP-complete even when…

Data Structures and Algorithms · Computer Science 2026-04-08 Julien Baste

A graph G is called well-indumatched if all of its maximal induced matchings have the same size. In this paper we characterize all well-indumatched trees. We provide a linear time algorithm to decide if a tree is well-indumatched or not.…

Discrete Mathematics · Computer Science 2019-12-18 S. Akbari , T. Ekim , A. H. Ghodrati , S. Zare

Let $G$ be a graph and $a(G)$, LIF$(G)$ denote the maximum orders of an induced forest and an induced linear forest of $G$, respectively. It is well-known that if $G$ is an $r$-regular graph of order $n$, then $a(G) \geq \frac{2}{r+1}n$. In…

Combinatorics · Mathematics 2019-11-07 Saieed Akbari , Alireza Amanihamedani , Sepehr Mousavi , Hesam Nikpey , Soheil Sheybani
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