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We give an Ore-Type condition sufficient for a graph G to have a spanning tree with a specified degree sequence.

Combinatorics · Mathematics 2021-02-03 María Elena Martínez-Cuero , Eduardo Rivera-Campo

A spanning tree $T$ of a connected graph $G$ is a subgraph of $G$ that is a tree covers all vertices of $G$. The leaf distance of $T$ is defined as the minimum of distances between any two leaves of $T$. A fractional matching of a graph $G$…

Combinatorics · Mathematics 2025-07-16 Sizhong Zhou

Let $G$ be a connected graph. If $G$ contains a matching of size $k$, and every matching of size $k$ is contained in a perfect matching of $G$, then $G$ is said to be \emph{$k$-extendable}. A $k$-regular spanning subgraph of $G$ is called a…

Combinatorics · Mathematics 2022-11-18 Dandan Fan , Huiqiu Lin

In this article, we extend Moon's classic formula for counting spanning trees in complete graphs containing a fixed spanning forest to complete bipartite graphs. Let $(X,Y)$ be the bipartition of the complete bipartite graph $K_{m,n}$ with…

Combinatorics · Mathematics 2022-03-04 Fengming Dong , Jun Ge

In this paper, we present some new results describing connections between the spectrum of a regular graph and its generalized connectivity, toughness, and the existence of spanning trees with bounded degree.

Combinatorics · Mathematics 2016-02-19 Sebastian M. Cioabă , Xiaofeng Gu

Let $T$ be a tree. A vertex of degree one is a \emph{leaf} of $T$ and a vertex of degree at least three is a \emph{branch vertex} of $T$. A graph is said to be claw-free if it does not contain $K_{1,3}$ as an induced subgraph. In this…

Combinatorics · Mathematics 2025-11-26 Pham Hoang Ha , Nguyen Gia Hien

We prove that for fixed $k$, every $k$-uniform hypergraph on $n$ vertices and of minimum codegree at least $n/2+o(n)$ contains every spanning tight $k$-tree of bounded vertex degree as a sub\-graph. This generalises a well-known result of…

Combinatorics · Mathematics 2023-06-12 Matías Pavez-Signé , Nicolás Sanhueza-Matamala , Maya Stein

The {\sc Directed Maximum Leaf Out-Branching} problem is to find an out-branching (i.e. a rooted oriented spanning tree) in a given digraph with the maximum number of leaves. In this paper, we obtain two combinatorial results on the number…

Data Structures and Algorithms · Computer Science 2008-03-06 N Alon , F. V. Fomin , G. Gutin , M. Krivelevich , S. Saurabh

We consider all spanning trees of a complete simple graph $\Gamma$ on $n$ vertices that contain a given $m-$forest $F$. We show that the number of such spanning trees, $\tau(F)$, doesn't depend on the structure of $F$ and is completely…

Combinatorics · Mathematics 2022-10-18 Peter J. Cameron , Michael Kagan

We prove that every amenable one-ended Cayley graph has an invariant spanning tree of one end. More generally, for any 1-ended amenable unimodular random graph we construct a factor of iid percolation (jointly unimodular subgraph) that is…

Probability · Mathematics 2020-05-11 Adam Timar

Let $G$ be a graph (with multiple edges allowed) and let $T$ be a tree in $G$. We say that $T$ is $\textit{even}$ if every leaf of $T$ belongs to the same part of the bipartition of $T$, and that $T$ is $\textit{weakly even}$ if every leaf…

Nikiforov (LAA, 2010) conjectured that for given integer $k$, any graph $G$ of sufficiently large order $n$ with spectral radius $\mu(G)\geq \mu(S_{n,k})$ contains all trees of order $2k+2$, unless $G=S_{n,k}$, where $S_{n,k}=K_k\vee…

Combinatorics · Mathematics 2018-08-03 Xinmin Hou , Boyuan Liu , Shicheng Wang , Jun Gao , Chenhui Lv

This paper considers the conjecture by Gr\"unbaum that every planar 3-connected graph has a spanning tree $T$ such that both $T$ and its co-tree have maximum degree at most 3. Here, the co-tree of $T$ is the spanning tree of the dual…

Discrete Mathematics · Computer Science 2013-12-17 Therese Biedl

We call a tree $T$ is \emph{even} if every pair of its leaves is joined by a path of even length. Jackson and Yoshimoto~[J. Graph Theory, 2024] conjectured that every $r$-regular nonbipartite connected graph $G$ has a spanning even tree.…

Combinatorics · Mathematics 2024-09-11 Jiangdong Ai , Zhipeng Gao , Xiangzhou Liu , Jun Yue

Let $T$ be a tree, a vertex of degree one is a \emph{leaf} of $T$ and a vertex of degree at least three is a \emph{branch vertex} of $T$. The {\it reducible stem } of $T$ is the smallest subtree that contains all branch vertices of $T$. In…

Combinatorics · Mathematics 2023-05-15 Pham Hoang Ha , Le Dinh Nam , Ngoc Diep Pham

Partially answering a question of Paul Seymour, we obtain a sufficient eigenvalue condition for the existence of $k$ edge-disjoint spanning trees in a regular graph, when $k\in \{2,3\}$. More precisely, we show that if the second largest…

Combinatorics · Mathematics 2013-12-10 Sebastian M. Cioabă , Wiseley Wong

A spanning tree of a graph $G$ is a connected acyclic spanning subgraph of $G$. We consider enumeration of spanning trees when $G$ is a $2$-tree, meaning that $G$ is obtained from one edge by iteratively adding a vertex whose neighborhood…

Discrete Mathematics · Computer Science 2016-07-21 P. Renjith , N. Sadagopan , Douglas B. West

A classical result of Koml\'os, S\'ark\"ozy and Szemer\'edi shows that every large $n$-vertex graph with minimum degree at least $(1/2+\gamma)n$ contains all spanning trees of bounded degree. We generalised this result to loose spanning…

Combinatorics · Mathematics 2025-02-10 Yaobin Chen , Allan Lo

Let $G$ be a graph and $T_1,T_2$ be two spanning trees of $G$. We say that $T_1$ can be transformed into $T_2$ via an edge flip if there exist two edges $e \in T_1$ and $f$ in $T_2$ such that $T_2= (T_1 \setminus e) \cup f$. Since spanning…

Data Structures and Algorithms · Computer Science 2020-06-26 Nicolas Bousquet , Takehiro Ito , Yusuke Kobayashi , Haruka Mizuta , Paul Ouvrard , Akira Suzuki , Kunihiro Wasa

Given a graph $G=(V,E)$, a tree cover is a collection of trees $\mathcal{T}=\{T_1,T_2,...,T_q\}$, such that for every pair of vertices $u,v\in V$ there is a tree $T\in\mathcal{T}$ that contains a $u-v$ path with a small stretch. If the…

Data Structures and Algorithms · Computer Science 2025-11-11 Michael Elkin , Idan Shabat