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Bollob\'{a}s and Scott [5] conjectured that every graph $G$ has a balanced bipartite spanning subgraph $H$ such that for each $v\in V(G)$, $d_H(v)\ge (d_G(v)-1)/2$. In this paper, we show that every graphic sequence has a realization for…

Combinatorics · Mathematics 2017-01-26 Yuliang Ji , Jie Ma , Juan Yan , Xingxing Yu

In this paper we have given an algorithmic proof of an long standing Barnette's conjecture (1969) that every 3-connected bipartite cubic planar graph is hamiltonian. Our method is quite different than the known approaches and it rely on the…

General Mathematics · Mathematics 2009-04-23 I. Cahit

The Ascending Subgraph Decomposition (ASD) Conjecture asserts that every graph $G$ with ${n+1\choose 2}$ edges admits an edge decomposition $G=H_1\oplus\cdots \oplus H_n$ such that $H_i$ has $i$ edges and it is isomorphic to a subgraph of…

Combinatorics · Mathematics 2015-12-08 Anna Lladó , Josep Maria Aroca

The Strong Nine Dragon Tree Conjecture asserts that for any integers $k$ and $d$ any graph with fractional arboricity at most $k + \frac{d}{d+k+1}$ decomposes into $k+1$ forests, such that for at least one of the forests, every connected…

Combinatorics · Mathematics 2020-07-15 Benjamin Moore

In this paper, we prove the following conjecture proposed by Gould, Hirohata and Keller [Discrete Math. submitted]: Let $G$ be a graph of sufficiently large order. If $\sigma_t(G) \geq 2kt - t + 1$ for any two integers $k \geq 2$ and $t…

Combinatorics · Mathematics 2017-07-11 Fuhong Ma , Jin Yan

The weak minor G of a graph G is the graph obtained from G by a sequence of edge-contraction operations on G. A weak-minor-closed family of upper embeddable graphs is a set G of upper embeddable graphs that for each graph G in G, every weak…

Combinatorics · Mathematics 2012-03-06 Guanghua Dong , Ning Wang , Yuanqiu Huang , Han Ren , Yanpei Liu

In this paper, we are motivated by the conjectures proposed by C.~Bender \textit{et al.}, \cite{C} in 2024. We have settled the first two conjectures negatively by providing a counter example in \cite{KTJ}, whereas in this paper, we prove…

Combinatorics · Mathematics 2026-04-20 Anagha Khiste , Ganesh Tarte , Vinayak Joshi

The girth of a graph is defined as the length of a shortest cycle in the graph. A $(k; g)$-cage is a graph of minimum order among all $k$-regular graphs with girth $g$. A cycle $C$ in a graph $G$ is termed nonseparating if the graph…

Combinatorics · Mathematics 2024-10-10 Xiang-Feng Pan , Jing-Zhong Mao , Hui-Qing Liu

Let $G=(V,E)$ be a graph. A subset $D\subseteq V$ is a dominating set if every vertex not in $D$ is adjacent to a vertex in $D$. The domination number of $G$, denoted by $\gamma(G)$, is the smallest cardinality of a dominating set of $G$.…

Combinatorics · Mathematics 2014-03-13 Fu-Tao Hu , Moo Young Sohn

The arboricity $\Gamma(G)$ of an undirected graph $G = (V,E)$ is the minimal number such that $E$ can be partitioned into $\Gamma(G)$ forests. Nash-Williams' formula states that $k = \lceil \gamma(G) \rceil$, where $\gamma(G)$ is the…

Combinatorics · Mathematics 2023-07-31 Sebastian Mies , Benjamin Moore

A signed graph is one that features two types of edges: positive and negative. Balanced signed graphs are those in which all cycles contain an even number of positive edges. In the adjacency matrix of a signed graph, entries can be $0$,…

Combinatorics · Mathematics 2024-08-15 Cristian M. Conde , Ezequiel Dratman , Luciano N. Grippo

The twin-width of a graph $G$ is the minimum integer $d$ such that $G$ has a $d$-contraction sequence, that is, a sequence of $|V(G)|-1$ iterated vertex identifications for which the overall maximum number of red edges incident to a single…

Discrete Mathematics · Computer Science 2020-06-18 Édouard Bonnet , Colin Geniet , Eun Jung Kim , Stéphan Thomassé , Rémi Watrigant

By finding orthogonal representation for a family of simple connected called $\delta$-graphs it is possible to show that $\delta$-graphs satisfy delta conjecture. An extension of the argument to graphs of the form…

Combinatorics · Mathematics 2018-06-20 Pedro Díaz Navarro

The 3-decomposition conjecture is wide open. It asserts that every finite connected cubic graph can be decomposed into a spanning tree, a disjoint union of cycles, and a matching. We show that every such decomposition is derived from a…

Combinatorics · Mathematics 2022-02-22 Oliver Bachtler , Irene Heinrich

In 1984, Erd\H{o}s and Simonovits conjectured the following: given a bipartite graph $H$, there exist constants $\beta, C > 0$ such that any graph $G$ on $n$ vertices and $pn^2\geq C \mathrm{ex}(n, H)$ edges contains at least $\beta…

Combinatorics · Mathematics 2025-10-30 Zihao Jin , Sean Longbrake , Liana Yepremyan

Deciding whether a graph can be embedded in a grid using only unit-length edges is NP-complete, even when restricted to binary trees. However, it is not difficult to devise a number of graph classes for which the problem is polynomial, even…

Data Structures and Algorithms · Computer Science 2012-04-13 Vinícius G. P. de Sá , Guilherme D. da Fonseca , Raphael Machado , Celina M. H. de Figueiredo

In this paper, we characterize the class of {\em contraction perfect} graphs which are the graphs that remain perfect after the contraction of any edge set. We prove that a graph is contraction perfect if and only if it is perfect and the…

Combinatorics · Mathematics 2024-01-24 Alexandre Dupont-Bouillard , Pierre Fouilhoux , Roland Grappe , Mathieu Lacroix

The strong cycle double cover conjecture states that for every circuit $C$ of a bridgeless cubic graph $G$, there is a cycle double cover of $G$ which contains $C$. We conjecture that there is even a 5-cycle double cover $S$ of $G$ which…

Combinatorics · Mathematics 2012-11-12 Arthur Hoffmann-Ostenhof

We resolve two conjectures of Hri\v{n}\'{a}kov\'{a}, Knor and \v{S}krekovski (2019) concerning the relationship between the variable Wiener index and variable Szeged index for a connected, non-complete graph, one of which would imply the…

Combinatorics · Mathematics 2023-03-22 Stijn Cambie , John Haslegrave

Since the transformative workshop by the American Institute of Mathematics on the minimum rank of a graph, two longstanding open problems have captivated the community interested in the minimum rank of graphs: the graph complement…

Combinatorics · Mathematics 2025-06-02 Francesco Barioli , Shaun M. Fallat , Himanshu Gupta , Zhongshan Li
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