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相关论文: On rainbow thresholds

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We extend a recent breakthrough result relating expectation thresholds and actual thresholds to include some rainbow versions.

组合数学 · 数学 2023-12-25 Tolson Bell , Alan Frieze , Trent G. Marbach

A tree in an edge colored graph is said to be a rainbow tree if no two edges on the tree share the same color. Given two positive integers $k$, $\ell$ with $k\geq 3$, the \emph{$(k,\ell)$-rainbow index} $rx_{k,\ell}(G)$ of $G$ is the…

组合数学 · 数学 2013-10-21 Qingqiong Cai , Xueliang Li , Jiangli Song

A rainbow stacking of $r$-edge-colorings $\chi_1, \ldots, \chi_m$ of the complete graph on $n$ vertices is a way of superimposing $\chi_1, \ldots, \chi_m$ so that no edges of the same color are superimposed on each other. We determine a…

组合数学 · 数学 2024-05-24 Noga Alon , Colin Defant , Noah Kravitz

We define a generalization of threshold graphs which we call $k$-rainbow threshold graphs. We show that the collection of $k$-rainbow threshold graphs do not satisfy the $0$-$1$ law for first order logic and that asymptotically almost…

组合数学 · 数学 2025-04-16 Nathanael Ackerman , Mostafa Mirabi

We formulate and prove the generalizations of Friedman's free set and thin set theorems and of the rainbow Ramsey theorem to colorings of barriers. We analyze the strength of these theorems from the point of view of computability theory…

逻辑 · 数学 2026-05-06 Lorenzo Carlucci , Oriola Gjetaj

In this expository article, we give a gentle introduction to the Erd\H{o}s-R\'enyi random graphs and threshold phenomena that they exhibit. We also mildly introduce the Kahn-Kalai Conjecture with several intuitive examples, mainly targeting…

历史与综述 · 数学 2023-07-28 Jinyoung Park

Bal and DeBiasio [Partitioning random graphs into monochromatic components, Electron. J. Combin. 24 (2017), Paper 1.18] put forward a conjecture concerning the threshold for the following Ramsey-type property for graphs $G$: every…

组合数学 · 数学 2019-02-20 Yoshiharu Kohayakawa , Guilherme Oliveira Mota , Mathias Schacht

By a theorem of Drisko, any $2n-1$ matchings of size $n$ in a bipartite graph have a partial rainbow matching of size $n$. Inspired by discussion of Bar\'at, Gy\'arf\'as and S\'ark\"ozy, we conjecture that if $n$ is odd then the same is…

组合数学 · 数学 2018-07-10 Ron Aharoni , Eli Berger , Maria Chudnovsky , David Howard , Paul Seymour

Aharoni and Berger conjectured that in every proper edge-colouring of a bipartite multigraph by $n$ colours with at least $n+1$ edges of each colour there is a rainbow matching using every colour. This conjecture generalizes a longstanding…

组合数学 · 数学 2018-05-28 Alexey Pokrovskiy

Drisko proved that $2n-1$ matchings of size $n$ in a bipartite graph have a rainbow matching of size $n$. For general graphs it is conjectured that $2n$ matchings suffice for this purpose (and that $2n-1$ matchings suffice when $n$ is…

组合数学 · 数学 2021-02-17 Ron Aharoni , Joseph Briggs , Jinha Kim , Minki Kim

A rainbow matching for (not necessarily distinct) sets F_1,...,F_k of hypergraph edges is a matching consisting of k edges, one from each F_i. The aim of the paper is twofold - to put order in the multitude of conjectures that relate to…

组合数学 · 数学 2013-05-28 Ron Aharoni , Pierre Charbit , David Howard

Given a graph $G=(V,E)$ on $n$ vertices and an assignment of colours to its edges, a set of edges $S \subseteq E$ is said to be rainbow if edges from $S$ have pairwise different colours assigned to them. In this paper, we investigate…

组合数学 · 数学 2023-11-02 Deepak Bal , Alan Frieze , Pawel Pralat

A meta-conjecture of Coulson, Keevash, Perarnau and Yepremyan states that above the extremal threshold for a given spanning structure in a (hyper-)graph, one can find a rainbow version of that spanning structure in any suitably bounded…

组合数学 · 数学 2026-02-25 Amarja Kathapurkar , Patrick Morris , Guillem Perarnau

Let $G_{n,p}^{[\kappa]}$ denote the space of $n$-vertex edge coloured graphs, where each edge occurs independently with probability $p$. The colour of each existing edge is chosen independently and uniformly at random from the set…

组合数学 · 数学 2025-08-13 Colin Cooper , Alan Frieze

We extend a recent argument of Kahn, Narayanan and Park (Proceedings of the AMS, to appear) about the threshold for the appearance of the square of a Hamilton cycle to other spanning structures. In particular, for any spanning graph, we…

组合数学 · 数学 2021-06-21 Alberto Espuny Díaz , Yury Person

A subgraph of an edge-colored graph is called \emph{rainbow} if all of its edges have distinct colors. There has been much research on the topic of finding a large rainbow matching in a properly edge-colored graph, where a proper…

组合数学 · 数学 2026-05-28 Debsoumya Chakraborti , Po-Shen Loh

A path in an edge-colored graph is called a \emph{rainbow path} if all edges on it have pairwise distinct colors. For $k\geq 1$, the \emph{rainbow-$k$-connectivity} of a graph $G$, denoted $rc_k(G)$, is the minimum number of colors required…

组合数学 · 数学 2012-03-06 Jing He , Hongyu Liang

We consider the Erd\H{o}s-R\'enyi random graph process, which is a stochastic process that starts with $n$ vertices and no edges, and at each step adds one new edge chosen uniformly at random from the set of missing edges. Let…

组合数学 · 数学 2014-10-14 Deepak Bal , Patrick Bennett , Alan Frieze , Paweł Prałat

In this work, we develop a unified framework for establishing sharp threshold results for various Ramsey properties. To achieve this, we view such properties as non-colourability of auxiliary hypergraphs. Our main technical result gives…

组合数学 · 数学 2026-03-04 Ehud Friedgut , Eden Kuperwasser , Wojciech Samotij , Mathias Schacht

The work deals with the threshold probablity for r-colorability in the binomial model H(n,k,p) of a random k-uniform hypergraph. We prove a lower bound for this threshold which improves the previously known results in the wide range of the…

组合数学 · 数学 2017-12-01 Andrei Kupavskii , Dmitry Shabanov
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