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Let $Q_{d,p}$ be the random subgraph of the $d$-dimensional hypercube $\{0,1\}^d$, where each edge is retained independently with probability $p$. We study the asymptotic number of independent sets in $Q_{d,p}$ as $d \to \infty$ for a wide…

Combinatorics · Mathematics 2022-01-19 Gal Kronenberg , Yinon Spinka

Recently, Davies, Jenssen, Perkins, and Roberts gave a very nice proof of the result (due, in various parts, to Kahn, Galvin-Tetali, and Zhao) that the independence polynomial of a $d$-regular graph is maximized by disjoint copies of…

Combinatorics · Mathematics 2016-10-19 Jonathan Cutler , A. J. Radcliffe

Answering several questions of Duffus, Frankl and R\"odl, we give asymptotics for the logarithms of (i) the number of maximal antichains in the n-dimensional Boolean algebra and (ii) the numbers of maximal independent sets in the covering…

Combinatorics · Mathematics 2012-02-21 Liviu Ilinca , Jeff Kahn

This paper studies the problem of upper bounding the number of independent sets in a graph, expressed in terms of its degree distribution. For bipartite regular graphs, Kahn (2001) established a tight upper bound using an…

Combinatorics · Mathematics 2021-04-01 Igal Sason

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

We consider the algorithmic problem of finding large \textit{balanced} independent sets in sparse random bipartite graphs, and more generally the problem of finding independent sets with specified proportions of vertices on each side of the…

Data Structures and Algorithms · Computer Science 2023-07-27 Will Perkins , Yuzhou Wang

An independent vertex set of a graph is a set of vertices of the graph in which no two vertices are adjacent, and a maximal independent set is one that is not a proper subset of any other independent set. In this paper we count the number…

Combinatorics · Mathematics 2017-09-13 Seungsang Oh

Let $B(2d-1, d)$ be the subgraph of the hypercube $\mathcal{Q}_{2d-1}$ induced by its two largest layers. Duffus, Frankl and R\"odl proposed the problem of finding the asymptotics for the logarithm of the number of maximal independent sets…

Combinatorics · Mathematics 2025-05-02 József Balogh , Ce Chen , Ramon I. Garcia

We study the problem of constructing explicit sparse graphs that exhibit strong vertex expansion. Our main result is the first two-sided construction of imbalanced unique-neighbor expanders, meaning bipartite graphs where small sets…

Combinatorics · Mathematics 2024-01-17 Jun-Ting Hsieh , Theo McKenzie , Sidhanth Mohanty , Pedro Paredes

Write ${\cal I}(G)$ for the set of independent sets of a graph $G$ and $i(G)$ for $|{\cal I}(G)|$. It has been conjectured (by Alon and Kahn) that for an $N$-vertex, $d$-regular graph $G$, $$ i(G) \leq \left(2^{d+1}-1\right)^{N/2d}. $$ If…

Combinatorics · Mathematics 2010-07-29 David Galvin

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

We give a fully polynomial-time approximation scheme (FPTAS) to count the number of independent sets on almost every $\Delta$-regular bipartite graph if $\Delta\ge 53$. In the weighted case, for all sufficiently large integers $\Delta$ and…

Data Structures and Algorithms · Computer Science 2019-03-19 Chao Liao , Jiabao Lin , Pinyan Lu , Zhenyu Mao

Fix a positive integer $n$ and consider the bipartite graph whose vertices are the $3$-element subsets and the $2$-element subsets of $[n]=\{1,2,\dots,n\}$, and there is an edge between $A$ and $B$ if $A\subset B$. We prove that the…

Combinatorics · Mathematics 2024-06-25 Thomas Kalinowski , Uwe Leck

We enumerate the independent sets of several classes of regular and almost regular graphs and compute the corresponding generating functions. We also note the relations between these graphs and other combinatorial objects and, in some…

Combinatorics · Mathematics 2007-05-23 Alexander Burstein , Sergey Kitaev , Toufik Mansour

We give a randomized algorithm that approximates the number of independent sets in a dense, regular bipartite graph -- in the language of approximate counting, we give an FPRAS for #BIS on the class of dense, regular bipartite graphs.…

Data Structures and Algorithms · Computer Science 2023-07-20 Charlie Carlson , Ewan Davies , Alexandra Kolla , Aditya Potukuchi

In a recent work on the bipartite Erd\H{o}s-R\'{e}nyi graph, Do et al. (2023) established upper bounds on the number of connected labeled bipartite graphs with a fixed surplus. We use some recent encodings of bipartite random graphs in…

Combinatorics · Mathematics 2024-11-15 David Clancy

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

Many enumeration problems in combinatorics, including such fundamental questions as the number of regular graphs, can be expressed as high-dimensional complex integrals. Motivated by the need for a systematic study of the asymptotic…

Combinatorics · Mathematics 2017-12-29 Mikhail Isaev , Brendan D. McKay

A theorem of Shearer states that every $n$-vertex triangle-free graph of maximum degree $d \geq 2$ contains an independent set of size at least $(d\log d - d + 1)/(d - 1)^2 \cdot n$. Ajtai, Koml\'{o}s, Pintz, Spencer and Szemer\'{e}di…

Combinatorics · Mathematics 2025-12-18 Jacques Verstraete , Chase Wilson

We construct an infinite family of bounded-degree bipartite unique-neighbour expander graphs with arbitrarily unbalanced sides. Although weaker than the lossless expanders constructed by Capalbo et al., our construction is simpler and may…

Combinatorics · Mathematics 2023-01-10 Ron Asherov , Irit Dinur