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We asymptotically determine the size of the largest family F of subsets of {1,...,n} not containing a given poset P if the Hasse diagram of P is a tree. This is a qualitative generalization of several known results including Sperner's…

Combinatorics · Mathematics 2009-11-21 Boris Bukh

A Laver tree is a tree in which each node splits infinitely often. A Hechler tree is a tree in which each node splits cofinitely often. We show that every analytic set is either disjoint from the branches of a Heckler tree or contains the…

Logic · Mathematics 2012-04-25 Arnold W. Miller

We extend classical results on simple varieties of trees (asymptotic enumeration, average behavior of tree parameters) to trees counted by their number of leaves. Motivated by genome comparison of related species, we then apply these…

Combinatorics · Mathematics 2016-10-03 Mathilde Bouvel , Marni Mishna , Cyril Nicaud

We look for partition theorems for large subtrees for suitable uncountable trees and colourings. We concentrate on sub-trees of $^{\kappa \ge} 2$ expanded by a well ordering of each level. Unlike earlier works, we do not ask the embedding…

Logic · Mathematics 2026-01-06 Saharon Shelah

We investigate the existence of perfect homogeneous sets for analytic colorings. An analytic coloring of X is an analytic subset of [X]^N, where N>1 is a natural number. We define an absolute rank function on trees representing analytic…

Logic · Mathematics 2007-05-23 Wieslaw Kubís , Saharon Shelah

In this work, we study the color discrepancy of spanning trees in random graphs. We show that for the Erd\H{o}s-R\'enyi random graph $G(n,p)$ with $p$ above the connectivity threshold, the following holds with high probability: in every…

Combinatorics · Mathematics 2025-11-10 Wenchong Chen , Xiao-Chuan Liu , Xu Yang

Real-world observational datasets and machine learning have revolutionized data-driven decision-making, yet many models rely on empirical associations that may be misleading due to confounding and subgroup heterogeneity. Simpson's paradox…

Machine Learning · Computer Science 2026-03-03 Xian Teng , Yu-Ru Lin

Patterns on numerical semigroups are multivariate linear polynomials, and they are said to be admissible if there exists a numerical semigroup such that evaluated at any nonincreasing sequence of elements of the semigroup gives integers…

Number Theory · Mathematics 2012-11-06 Maria Bras-Amorós , Pedro A. García-Sánchez , Albert Vico-Oton

A well-known open problem in graph theory asks whether Stanley's chromatic symmetric function, a generalization of the chromatic polynomial of a graph, distinguishes between any two non-isomorphic trees. Previous work has proven the…

Combinatorics · Mathematics 2020-02-05 Jake Huryn

The time-ordered multilayer integrals have long been cited as major challenges in the analytical study of cosmological correlators and wavefunction coefficients. The recently proposed family tree decomposition technique solved these time…

High Energy Physics - Theory · Physics 2025-09-04 Bingchu Fan , Zhong-Zhi Xianyu

The degree chromatic polynomial $Pm(G,k)$ of a graph $G$ counts the number of $k$-colorings in which no vertex has $m$ adjacent vertices of its same color. We prove Humpert and Martin's conjecture on the leading terms of the degree…

Combinatorics · Mathematics 2014-10-20 Diego Cifuentes

The reconstruction of a central tendency `species tree' from a large number of conflicting gene trees is a central problem in systematic biology. Moreover, it becomes particularly problematic when taxon coverage is patchy, so that not all…

Populations and Evolution · Quantitative Biology 2013-07-22 Mike Steel

Stanley asked whether a tree is determined up to isomorphism by its chromatic symmetric function. We approach Stanley's problem by studying the relationship between the chromatic symmetric function and other invariants. First, we prove…

Combinatorics · Mathematics 2024-07-24 José Aliste-Prieto , Jeremy L. Martin , Jennifer D. Wagner , José Zamora

Analysis of probability distributions conditional on species trees has demonstrated the existence of anomalous ranked gene trees (ARGTs), ranked gene trees that are more probable than the ranked gene tree that accords with the ranked…

Populations and Evolution · Quantitative Biology 2014-07-14 Filippo Disanto , Noah A. Rosenberg

Halin conjectured 20 years ago that a graph has a normal spanning tree if and only if every minor of it has countable colouring number. We prove Halin's conjecture. This implies a forbidden minor characterisation for the property of having…

Combinatorics · Mathematics 2022-07-12 Max Pitz

We define a family of vertex colouring games played over a pair of graphs or digraphs $(G,H)$ by players $\forall$ and $\exists$. These games arise from work on a longstanding open problem in algebraic logic. It is conjectured that there is…

Combinatorics · Mathematics 2021-12-09 Rob Egrot , Robin Hirsch

We consider the rooted trees which not have isomorphic representation and introduce a conception of complexity a natural number also. The connection between quantity such trees with $n$ edges and a complexity of natural number $n$ is…

Combinatorics · Mathematics 2012-05-03 B. S. Kochkarev

To every tree we associate a filtered cochain complex. Its cohomology and the corresponding spectral sequence have clear combinatorial description. If a tree is the Dynkin diagram of a simple plane curve singularity, the graded Euler…

Combinatorics · Mathematics 2009-01-12 E. Gorsky

The notion of tree entropy was introduced by the author as a normalized limit of the number of spanning trees in finite graphs, but is defined on random infinite rooted graphs. We give some new expressions for tree entropy; one uses…

Combinatorics · Mathematics 2010-04-27 Russell Lyons

A well-known theorem of Sperner describes the largest collections of subsets of an $n$-element set none of which contains another set from the collection. Generalising this result, Erd\H{o}s characterised the largest families of subsets of…

Combinatorics · Mathematics 2017-08-09 Wojciech Samotij
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