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An infinite integer matrix A is called image partition regular if, whenever the natural numbers are finitely coloured, there is an integer vector x such that Ax is monochromatic. Given an image partition regular matrix A, can we also insist…

Combinatorics · Mathematics 2013-12-20 Ben Barber , Imre Leader

Csikv\'ari, Gyarmati, and S\'ark\"ozy showed that the equation $x+y = z^2$ is not partition regular (PR) over $\mathbb{N}$ and asked if the equation $x+y = wz$ is PR over $\mathbb{N}$. Bergelson and Hindman independently answered this…

Combinatorics · Mathematics 2023-06-27 Sohail Farhangi , Richard Magner

Let $a_{r,s}(n)$ denote the number of mutlicolored partitions of $n$, wherein both even parts and odd parts may appear in one of $r$-colors and $s$-colors, respectively, for fixed $r,s\ge 1$. The paper aims to study arithmetic properties…

Combinatorics · Mathematics 2026-01-23 M. P. Thejitha , James A. Sellers , S. N. Fathima

Erd\H{o}s & Graham ask whether the equation $x^2+y^2=z^2$ is partition regular, i.e. whether it has a finite Rado number. This note provides a lower bound and also states results in the affirmative for two similar quadratic equations.

Combinatorics · Mathematics 2015-01-22 Kellen Myers

Let P be a polygon whose vertices have been colored (labeled) cyclically with the numbers 1,2,...,c. Motivated by conjectures of Propp, we are led to consider partitions of P into k-gons which are proper in the sense that each k-gon…

Combinatorics · Mathematics 2007-05-23 Bruce Sagan

Generalised Pythagorean triples are integer tuples $(x,y,z)$ satisfying the equation $E_{a,b,c}: ax^2+by^2+cz^2=0$. A significant amount of research has been devoted towards understanding generalised Pythagorean triples and, in particular,…

Number Theory · Mathematics 2025-06-16 Pedro-José Cazorla García

We present an explicit family of hypergraphs with arbitrarily large uniformity and chromatic number that admit realizations in both geometric and number-theoretic settings. As an application, we give a new proof of a theorem of Chen, Pach,…

Combinatorics · Mathematics 2026-02-23 Gábor Damásdi

We study Rado functionals and the maximal condition (first introduced by J. M. Barret et al.) in terms of the partition regularity of mixed systems of linear equations and inequalities. By strengthening the maximal Rado condition, we…

Combinatorics · Mathematics 2022-09-19 Paulo Henrique Arruda , Lorenzo Luperi Baglini

We consider systems of $n$ diagonal equations in $k$th powers. Our main result shows that if the coefficient matrix of such a system is sufficiently non-singular, then the system is partition regular if and only if it satisfies Rado's…

Number Theory · Mathematics 2020-03-25 Jonathan Chapman

Consider an arbitrary coloring of integers with finite number of colors. Is it true that there are x, y such that x + y, xy and x have the same color? This is a well-known question of Ramsey theory has not solved yet. In the article we give…

Combinatorics · Mathematics 2009-09-18 I. D. Shkredov

We extend classical results of Rado on partition regularity of systems of linear equations with integer coefficients to the case when the coefficient ring is either an arbitrary integral domain or a noetherian ring. In particular, we show…

Combinatorics · Mathematics 2021-03-08 Jakub Byszewski , Elżbieta Krawczyk

Every partition of [[omega_1]^{< omega}]^2 into finitely many pieces has a cofinal homogeneous set. Furthermore, it is consistent that every directed partially ordered set satisfies the partition property if and only if it has finite…

Logic · Mathematics 2008-02-03 Thomas Jech , Saharon Shelah

We study density and partition properties of polynomial equations in prime variables. We consider equations of the form $a_1h(x_1) + \cdots + a_sh(x_s)=b$, where the $a_i$ and $b$ are fixed coefficients, and $h$ is an arbitrary integer…

Number Theory · Mathematics 2024-11-27 Jonathan Chapman , Sam Chow

The parity of the partition function $p(n)$ remains strikingly mysterious. Beyond a handful of fragmentary results, essentially nothing is known about the distribution of parity. We prove a uniform result on quadratic progressions. If…

Number Theory · Mathematics 2025-10-06 Ken Ono

Let $a_k(n)$ denote the number of partitions of $n$ wherein even parts come in only one color, while the odd parts may be ``colored" with one of $k$ colors, for fixed $k$. In this note, we find some congruences for $a_k(n)$ in the spirit of…

Number Theory · Mathematics 2026-01-21 Anjelin Mariya Johnson , James A. Sellers , S. N. Fathima

We provide a sufficient condition for solvability of a system of real quadratic equations $p_i(x)=y_i$, $i=1, \ldots, m$, where $p_i: {\mathbb R}^n \longrightarrow {\mathbb R}$ are quadratic forms. By solving a positive semidefinite…

Optimization and Control · Mathematics 2021-10-05 Alexander Barvinok , Mark Rudelson

For any partition of a positive integer we consider the chess (or draughts) colouring of its associated Ferrers graph. Let b denote the total number of black unit squares, and w the number of white squares. In this note we characterize all…

Combinatorics · Mathematics 2007-05-23 K. De Naeghel , N. Marconnet

Let $b^{k}_{\ell,m}(n)$ denotes the number of $k-$colored partitions of $n$ into parts that are not multiples of $\ell$ or $m$. We establish several congruence relations for $b_{\ell,m}(n)$. For instance, for any nonnegative integer $n$…

Combinatorics · Mathematics 2025-05-20 Yashas N. , C. Shivashankar , S. Chandankumar

Raimi's theorem guarantees the existence of a partition of $\mathbb{N}$ into two parts with an unavoidable intersection property: for any finite coloring of $\mathbb{N}$, some color class intersects both parts infinitely many times, after…

Combinatorics · Mathematics 2026-01-01 Norbert Hegyvari , Janos Pach , Thang Pham

Let $G$ be a finite abelian group with exponent $n$, and let $r$ be a positive integer. Let $A$ be a $k\times m$ matrix with integer entries. We show that if $A$ satisfies some natural conditions and $|G|$ is large enough then, for each…

Combinatorics · Mathematics 2012-03-13 Oriol Serra , Lluís Vena