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We examine the Maximum Independent Set Problem in an undirected graph. The main result is that this problem can be considered as the solving the same problem in a subclass of the weighted normal twin-orthogonal graphs. The problem is…

Data Structures and Algorithms · Computer Science 2016-03-08 Anatoly D. Plotnikov

An independent set in a graph $G$ is a set $S$ of pairwise non-adjacent vertices in $G$. A family $\mathcal{F}$ of independent sets in $G$ is called a $k$-independence covering family if for every independent set $I$ in $G$ of size at most…

Discrete Mathematics · Computer Science 2023-08-31 Michael Kuhn , Daniel Lokshtanov , Zachary Miller

In this paper, connections between independent sets and the variety of mutual-visibility sets are studied. It is proved that every outer mutual-visibility set of a graph is independent if and only if the graph is distance edge-critical.…

Combinatorics · Mathematics 2026-03-02 Jing Tian , Csilla Bujtás , Sandi Klavžar

We prove a transfer theorem for hereditary classes of $(r+1)$-uniform hypergraphs. Let $\mathcal H$ be such a class, and for $H\in\mathcal H$ write $\Delta(H)$ and $d(H)$ for the maximum degree and average degree of $H$, respectively. We…

Combinatorics · Mathematics 2026-05-08 Jing Yu , Junchi Zhang

We study the problems of bounding the number weak and strong independent sets in $r$-uniform, $d$-regular, $n$-vertex linear hypergraphs with no cross-edges. In the case of weak independent sets, we provide an upper bound that is tight up…

Combinatorics · Mathematics 2021-07-06 Emma Cohen , Will Perkins , Michail Sarantis , Prasad Tetali

A set is called r-independent, if every two vertices of it are in distance greater then r. In the r-independent set problem with parameter k, we ask whether in a given graph G there exists an r-independent set of size k. In this work we…

Data Structures and Algorithms · Computer Science 2019-12-03 Grzegorz Fabiański

We establish several properties of the integrated density of states for random quantum graphs: Under appropriate ergodicity and amenability assumptions, the integrated density of states can be defined using an exhaustion procedure by…

Spectral Theory · Mathematics 2015-05-13 Daniel Lenz , Norbert Peyerimhoff , Olaf Post , Ivan Veselic'

By Brook's Theorem, every n-vertex graph of maximum degree at most Delta >= 3 and clique number at most Delta is Delta-colorable, and thus it has an independent set of size at least n/Delta. We give an approximate characterization of graphs…

Discrete Mathematics · Computer Science 2019-11-05 Zdenek Dvorak , Bernard Lidicky

A graph $G$ is well-covered if all its maximal stable sets have the same size, denoted by alpha(G) (M. D. Plummer, 1970). If for any $k$ the $k$-th coefficient of a polynomial I(G;x) is equal to the number of stable sets of cardinality $k$…

Combinatorics · Mathematics 2007-05-23 Vadim E. Levit , Eugen Mandrescu

We investigate when the independence complex of $G[H]$, the lexicographical product of two graphs $G$ and $H$, is either vertex decomposable or shellable. As an application, we construct an infinite family of graphs with the property that…

Combinatorics · Mathematics 2015-05-13 Kevin N. Vander Meulen , Adam Van Tuyl

A polyhedral graph is a $3$-connected planar graph. We find the least possible order $p(k,a)$ of a polyhedral graph containing a $k$-independent set of size $a$ for all positive integers $k$ and $a$. In the case $k = 1$ and $a$ even, we…

Combinatorics · Mathematics 2023-01-02 Sébastien Gaspoz , Riccardo W. Maffucci

An independent set in a graph is a set of pairwise non-adjacent vertices, and alpha(G) is the size of a maximum independent set in the graph G. A matching is a set of non-incident edges, while mu(G) is the cardinality of a maximum matching.…

Discrete Mathematics · Computer Science 2011-05-12 Vadim E. Levit , Eugen Mandrescu

A $k$-uniform hypergraph $M$ is set-homogeneous if it is countable (possibly finite) and whenever two finite induced subhypergraphs $U,V$ are isomorphic there is $g\in Aut(M)$ with $U^g=V$; the hypergraph $M$ is said to be homogeneous if in…

Logic · Mathematics 2022-02-22 Amir Assari , Narges Hosseinzadeh , Dugald Macpherson

Call a colouring of a graph \emph{distinguishing} if the only automorphism of this graph which preserves said colouring is the identity. Let $H$ be an arbitrary graph. We say that a graph $G$ is \emph{$H$-free} if $G$ does not contain an…

Combinatorics · Mathematics 2021-05-25 Marcin Stawiski

We consider the problem of devising algorithms to count exactly the number of independent sets of a graph G . We show that there is a polynomial time algorithm for this problem when G is restricted to the class of strongly orderable graphs,…

Discrete Mathematics · Computer Science 2021-01-07 Marc Heinrich , Haiko Müller

Let $G=(V,E)$ be a graph and $n$ a positive integer. Let $I_n(G)$ be the abstract simplicial complex whose simplices are the subsets of $V$ that do not contain an independent set of size $n$ in $G$. We study the collapsibility numbers of…

Combinatorics · Mathematics 2024-10-15 Minki Kim , Alan Lew

Settling Kahn's conjecture (2001), we prove the following upper bound on the number $i(G)$ of independent sets in a graph $G$ without isolated vertices: \[ i(G) \le \prod_{uv \in E(G)} i(K_{d_u,d_v})^{1/(d_u d_v)}, \] where $d_u$ is the…

Combinatorics · Mathematics 2019-08-19 Ashwin Sah , Mehtaab Sawhney , David Stoner , Yufei Zhao

In this paper, we count the number of independent sets of a type of graph $G(\mathcal{A},q)$ associated to some hyperplane arrangement $\mathcal{A}$, which is a generalization of the construction of graphical arrangements. We show that when…

Combinatorics · Mathematics 2020-07-30 Nicholas Guo , Guangyi Yue

For a graph $G$, its $k$-th power $G^k$ is constructed by placing an edge between two vertices if they are within distance $k$ of each other. The $k$-independence number $\alpha_k(G)$ is defined as the independence number of $G^k$. By using…

Combinatorics · Mathematics 2024-11-15 Aida Abiad , Jiang Zhou

We consider a family of distance graphs in $\mathbb{R}^n$ and find its independent numbers in some cases. Define graph $J_{\pm}(n,k,t)$ in the following way: the vertex set consists of all vectors from $\{-1,0,1\}^n$ with $k$ nonzero…

Combinatorics · Mathematics 2022-10-06 Danila Cherkashin , Sergei Kiselev