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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

We prove that there exists an absolute constant $C>0$ such that, for any positive integer $k$, every graph $G$ with minimum degree at least $Ck$ admits a vertex-partition $V(G)=S\cup T$, where both $G[S]$ and $G[T]$ have minimum degree at…

Combinatorics · Mathematics 2023-06-16 Jie Ma , Hehui Wu

The Gyarfas-Sumner conjecture asserts that if H is a tree then every graph with bounded clique number and very large chromatic number contains H as an induced subgraph. This is still open, although it has been proved for a few simple…

Combinatorics · Mathematics 2018-12-06 Maria Chudnovsky , Alex Scott , Paul Seymour

An immersion of a graph $H$ into a graph $G$ is a one-to-one mapping $f:V(H) \to V(G)$ and a collection of edge-disjoint paths in $G$, one for each edge of $H$, such that the path $P_{uv}$ corresponding to edge $uv$ has endpoints $f(u)$ and…

Combinatorics · Mathematics 2011-01-14 Matt DeVos , Zdeněk Dvořák , Jacob Fox , Jessica McDonald , Bojan Mohar , Diego Scheide

A drawing of a given (abstract) tree that is a minimum spanning tree of the vertex set is considered aesthetically pleasing. However, such a drawing can only exist if the tree has maximum degree at most 6. What can be said for trees of…

Computational Geometry · Computer Science 2015-11-17 Ferran Hurtado , Giuseppe Liotta , David R. Wood

We prove that if T is a tree on n vertices wih maximum degree D and the edge probability p(n) satisfies: np>c*max{D*logn,n^{\epsilon}} for some constant \epsilon>0, then with high probability the random graph G(n,p) contains a copy of T.…

Combinatorics · Mathematics 2010-08-19 Michael Krivelevich

We prove that there exists $C>0$ such that any $(n+Ck)$-vertex tournament contains a copy of every $n$-vertex oriented tree with $k$ leaves, improving the previously best known bound of $n+O(k^2)$ vertices to give a result tight up to the…

Combinatorics · Mathematics 2022-07-06 Alistair Benford , Richard Montgomery

Bondy and Vince proved that a graph of minimum degree at least three contains two cycles whose lengths differ by one or two, which was conjectured by Erd\H{o}s. Gao, Li, Ma and Xie gave an average degree counterpart of Bondy-Vince's result,…

Combinatorics · Mathematics 2025-06-11 Binlong Li , Yufeng Pan , Lingjuan Shi

The average size of connected vertex subsets of a connected graph generalises a much-studied parameter for subtrees of trees. For trees, the possible values of this parameter are critically affected by the presence or absence of vertices of…

Combinatorics · Mathematics 2022-06-13 John Haslegrave

We consider packing tree degree sequences in this paper. We set up a conjecture that any arbitrary number of tree degree sequences without common leaves have edge disjoint tree realizations. This conjecture is known to be true for $2$ and…

Combinatorics · Mathematics 2017-04-12 Aravind Gollakota , William Hardt , Istvan Miklos

We show a general result known as the Erdos_Sos Conjecture: if $E(G)>{1/2}(k-1)n$ where $G$ has order $n$ then $G$ contains every tree of order $k+1$ as a subgraph.

Discrete Mathematics · Computer Science 2010-08-02 Jesse Gilbert

It follows from a classical result of Jordan that every tree with maximum degree at most $r$ containing a vertex set labeled by $[n]$, has a single-edge cut which separates two subsets $A,B \subset [n]$ for which $\min\{|A|,|B|\} \ge…

Combinatorics · Mathematics 2026-02-27 Sagi Snir , Raphael Yuster

In 2022, Gao, Huo, Liu, and Ma proved that every graph with minimum degree at least $k+1$ contains $k$ admissible cycles, where a set of $k$ cycles is said to be admissible if their lengths form an arithmetic progression with common…

Combinatorics · Mathematics 2026-04-03 Jifu Lin

This is the third of a series of four papers in which we prove the following relaxation of the Loebl-Komlos-Sos Conjecture: For every $\alpha>0$ there exists a number $k_0$ such that for every $k>k_0$ every $n$-vertex graph $G$ with at…

Combinatorics · Mathematics 2017-07-31 Jan Hladký , János Komlós , Diana Piguet , Miklós Simonovits , Maya J. Stein , Endre Szemerédi

In this paper, we address the problem of packing large trees in $G_{n,p}$. In particular, we prove the following result. Suppose that $T_1, \dotsc, T_N$ are $n$-vertex trees, each of which has maximum degree at most $(np)^{1/6} / (\log…

Combinatorics · Mathematics 2018-10-03 Asaf Ferber , Wojciech Samotij

Alon and Wormald showed that any graph with minimum degree d contains a spanning star forest in which every connected component is of size at least \Omega((d/\log d)^{1/3}). They asked if any connected graph with minimum degree at least d…

Combinatorics · Mathematics 2016-07-20 Codrut Grosu

We prove that if $D$ is a digraph of maximum outdegree and indegree at least $k$, and minimum semidegree at least $k/2$ that contains no oriented $4$-cycles, then $D$ contains each oriented tree $T$ with~$k$ arcs. This can be slightly…

Combinatorics · Mathematics 2024-11-21 Maya Stein , Ana Trujillo-Negrete

For a positive integer $k$, a graph is $k$-knitted if for each $k$-subset $S$ of vertices, and every partition of $S$ into disjoint parts $S_1, \ldots, S_t$ for some $t\ge 1$, one can find disjoint connected subgraphs $C_1, \ldots, C_t$…

Combinatorics · Mathematics 2019-06-11 Runrun Liu , Martin Rolek , Gexin Yu

Consider a host hypergraph $G$ which contains a spanning structure due to minimum degree considerations. We collect three results proving that if the edges of $G$ are sampled at the appropriate rate then the spanning structure still appears…

Combinatorics · Mathematics 2023-05-17 Huy Tuan Pham , Ashwin Sah , Mehtaab Sawhney , Michael Simkin

Dirac's theorem states that any $n$-vertex graph $G$ with even integer $n$ satisfying $\delta(G) \geq n/2$ contains a perfect matching. We generalize this to $k$-uniform linear hypergraphs by proving the following. Any $n$-vertex…

Combinatorics · Mathematics 2025-03-27 Seonghyuk Im , Hyunwoo Lee