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Related papers: On generic 3-rigidity of graphs

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We establish a best-possible minimum codegree condition for the existence of a perfect tiling of a $3$-uniform hypergraph $H$ with copies of the generalised triangle $T$, which is the 3-uniform hypergraph with five vertices $a, b, c, d, e$…

Combinatorics · Mathematics 2025-05-12 Candida Bowtell , Amarja Kathapurkar , Natasha Morrison , Richard Mycroft

A new layers method is presented for multipartite separability of density matrices from simple graphs. Full separability of tripartite states is studied for graphs on degree symmetric premise. The models are generalized to multipartite…

Quantum Physics · Physics 2018-09-18 Hui Zhao , Jing Yun Zhao , Naihuan Jing

A strongly separating path system in a graph $G$ is a collection $\mathcal{P}$ of paths in $G$ such that, for every two edges $e$ and $f$ of $G$, there is a paths in $\mathcal{P}$ with $e$ and not $f$, and vice-versa. The minimum number of…

Let $G$ be a uniformly chosen simple (labelled) random graph with given degree sequence $\boldsymbol{d}$ and let $X,Y,L$ be edge-disjoint graphs on the same vertex set as $G$. We investigate the probability that $X \subseteq G$ and that $G…

Combinatorics · Mathematics 2025-10-29 John Larkin , Brendan D. McKay , Fang Tian

Motivated by analogous questions in the setting of Steiner triple systems and Latin squares, Nenadov, Sudakov and Wagner [Completion and deficiency problems, Journal of Combinatorial Theory Series B, 2020] recently introduced the notion of…

Combinatorics · Mathematics 2021-08-17 Andrea Freschi , Joseph Hyde , Andrew Treglown

Recently Baranyai described a necessary combinatorial characterisation of graph rigidity for dimension 3. In this short note we provide a counter-example to the converse of the condition. Additionally, we provide an alternative proof to the…

Combinatorics · Mathematics 2026-01-28 Sean Dewar

Recently, Laplacian matrices of graphs are studied as density matrices in quantum mechanics. We continue this study and give conditions for separability of generalized Laplacian matrices of weighted graphs with unit trace. In particular, we…

Quantum Physics · Physics 2007-05-23 Chai Wah Wu

A graph is $\ell$-reconstructible if it is determined by its multiset of induced subgraphs obtained by deleting $\ell$ vertices. We prove that strongly regular graphs with at least six vertices are $2$-reconstructible.

Combinatorics · Mathematics 2022-10-24 Douglas B. West , Xuding Zhu

The famous Erd\H{o}s distinct distances problem asks the following: how many distinct distances must exist between a set of $n$ points in the plane? There are many generalisations of this question that ask one to consider different spaces…

Combinatorics · Mathematics 2025-05-13 Sean Dewar , Nora Frankl , Samuel Mansfield , Anthony Nixon , Jonathan Passant , Audie Warren

We consider random graphs in which the edges are allowed to be dependent. In our model the edge dependence is quite general, we call it $p$-robust random graph. It means that every edge is present with probability at least $p$, regardless…

Discrete Mathematics · Computer Science 2020-12-04 Zohre Ranjbar-Mojaveri , Andras Farago

A non-complete graph $G$ is said to be $t$-tough if for every vertex cut $S$ of $G$, the ratio of $|S|$ to the number of components of $G-S$ is at least $t$. The toughness $\tau(G)$ of the graph $G$ is the maximum value of $t$ such that $G$…

Combinatorics · Mathematics 2024-12-18 Kun Cheng , Chengli Li , Feng Liu

We describe a new random greedy algorithm for generating regular graphs of high girth: Let $k\geq 3$ and $c \in (0,1)$ be fixed. Let $n \in \mathbb{N}$ be even and set $g = c \log_{k-1} (n)$. Begin with a Hamilton cycle $G$ on $n$ vertices.…

Combinatorics · Mathematics 2020-06-30 Nati Linial , Michael Simkin

There is a sufficiently large $N\in h\mathbb{N}$ such that the following holds. If $G$ is a tripartite graph with $N$ vertices in each vertex class such that every vertex is adjacent to at least $2N/3+2h-1$ vertices in each of the other…

Combinatorics · Mathematics 2018-08-14 Kirsten Hogenson , Ryan R. Martin , Yi Zhao

We present a sufficient condition for a pair of finite integer sequences to be degree sequences of a bipartite graph, based only on the lengths of the sequences and their largest and smallest elements.

Combinatorics · Mathematics 2019-02-20 Grant Cairns , Stacey Mendan , Yuri Nikolayevsky

In this paper we shall be looking at several results relating Schur rings to sufficient conditions for a graph to be a graphical regular representation (GRR) of a finite group, and then applying these specifically in the case of certain…

Combinatorics · Mathematics 2024-01-09 Josef Lauri , Jonathan Ebejer

The 1-2-3 Conjecture, posed by Karo\'{n}ski, {\L}uczak and Thomason, asked whether every connected graph $G$ different from $K_2$ can be 3-edge-weighted so that every two adjacent vertices of $G$ get distinct sums of incident weights. The…

Combinatorics · Mathematics 2021-07-02 Jing-zhi Chang , Chao Yang , Zhi-xiang Yin , Bing Yao

By considering graphs as discrete analogues of Riemann surfaces, Baker and Norine (Adv. Math. 2007) developed a concept of linear systems of divisors for graphs. Building on this idea, a concept of gonality for graphs has been defined and…

Combinatorics · Mathematics 2016-07-12 Kevin Hendrey

This paper concerns fractional $K_s$-decompositions of multipartite graphs. For integers $r\ge s\ge 3$, we consider balanced $r$-partite graphs $G$ on $rn$ vertices. We establish necessary conditions for $G$ to admit a fractional…

Combinatorics · Mathematics 2026-04-29 Tao Feng , Hengrui Liu , Shikang Yu

Random geometric graphs (RGGs) are commonly used to model networked systems that depend on the underlying spatial embedding. We concern ourselves with the probability distribution of an RGG, which is crucial for studying its random…

Information Theory · Computer Science 2018-01-16 Mihai-Alin Badiu , Justin P. Coon

The toughness of a noncomplete graph $G$ is the maximum real number $t$ such that the ratio of $|S|$ to the number of components of $G-S$ is at least $t$ for every cutset $S$ of $G$, and the toughness of a complete graph is defined to be…

Combinatorics · Mathematics 2021-07-20 Yuping Gao , Songling Shan