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Related papers: Almost Empty Monochromatic Triangles in Planar Poi…

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In this paper, we consider the problem of counting almost empty monochromatic triangles in colored planar point sets, that is, triangles whose vertices are all assigned the same color and that contain only a few interior points.…

Let $S$ be a $k$-colored (finite) set of $n$ points in $\mathbb{R}^d$, $d\geq 3$, in general position, that is, no {$(d + 1)$} points of $S$ lie in a common $(d - 1)$}-dimensional hyperplane. We count the number of empty monochromatic…

Combinatorics · Mathematics 2012-10-29 Oswin Aichholzer , Ruy Fabila-Monroy , Thomas Hackl , Clemens Huemer , Jorge Urrutia

In a colouring of $\mathbb{R}^d$ a pair $(S,s_0)$ with $S\subseteq \mathbb{R}^d$ and with $s_0\in S$ is \emph{almost monochromatic} if $S\setminus \{s_0\}$ is monochromatic but $S$ is not. We consider questions about finding almost…

Combinatorics · Mathematics 2022-03-01 Nóra Frankl , Tamás Hubai , Dömötör Pálvölgyi

Let $S$ be a set of $n$ points in general position in the plane. Suppose that each point of $S$ has been assigned one of $k \ge 3$ possible colors and that there is the same number, $m$, of points of each color class. A polygon with…

Computational Geometry · Computer Science 2020-07-16 Ruy Fabila-Monroy , Daniel Perz , Ana Laura Trujillo-Negrete

Let $n,s,$ and $k$ be positive integers such that $k\geq 3$, $s\geq 3$ and $n\geq ks$. An $s$-matching $M_s$ in a $k$-uniform hypergraph is a set of $s$ pairwise disjoint edges. The anti-Ramsey number $\textrm{ar}(n,k,M_s)$ of an…

Combinatorics · Mathematics 2023-05-26 Mingyang Guo , Hongliang Lu , Xing Peng

Let $K_{n}^{r}$ denote the complete $r$-uniform hypergraph on $n$ vertices. A matching $M$ in a hypergraph is a set of pairwise vertex disjoint edges. Recent Ramsey-type results rely on lemmas about the size of monochromatic matchings. A…

We prove a known 2-coloring of the integers $[N] := \{1,2,3,\ldots,N\}$ minimizes the number of monochromatic arithmetic 3-progressions under certain restrictions. A monochromatic arithmetic progression is a set of equally-spaced integers…

Combinatorics · Mathematics 2023-01-03 Torin Greenwood , Jonathan Kariv , Noah Williams

We prove that for any planar convex body C there is a positive integer m with the property that any finite point set P in the plane can be three-colored such that there is no translate of C containing at least m points of P, all of the same…

Combinatorics · Mathematics 2026-01-21 Gábor Damásdi , Dömötör Pálvölgyi

In 1959, Goodman determined the minimum number of monochromatic triangles in a complete graph whose edge set is two-coloured. Goodman also raised the question of proving analogous results for complete graphs whose edge sets are coloured…

Combinatorics · Mathematics 2012-06-12 James Cummings , Daniel Král' , Florian Pfender , Konrad Sperfeld , Andrew Treglown , Michael Young

We prove that for any partition of the plane into a closed set $C$ and an open set $O$ and for any configuration $T$ of three points, there is a translated and rotated copy of $T$ contained in $C$ or in $O$. Apart from that, we consider…

Combinatorics · Mathematics 2011-04-29 Vit Jelinek , Jan Kyncl , Rudolf Stolar , Tomas Valla

A well-known result by Graham in Euclidean Ramsey Theory states that, for every positive real number $A$, every coloring of the plane with finite number of colors contains a monochromatic triangle of area $A$. We consider canonical versions…

Combinatorics · Mathematics 2026-03-17 Sukumar Das Adhikari , Tássio Naia , Oriol Serra

The (weak) chromatic number of a hypergraph $H$, denoted by $\chi(H)$, is the smallest number of colors required to color the vertices of $H$ so that no hyperedge of $H$ is monochromatic. For every $2\le k\le d+1$, denote by $\chi_L(k,d)$…

Combinatorics · Mathematics 2026-03-10 Seunghun Lee , Eran Nevo

Let $E(k, \ell)$ denote the smallest integer such that any set of at least $E(k, \ell)$ points in the plane, no three on a line, contains either an empty convex polygon with $k$ vertices or an empty pseudo-triangle with $\ell$ vertices. The…

Combinatorics · Mathematics 2012-10-18 Bhaswar B. Bhattacharya , Sandip Das

We show the existence of several infinite monochromatic patterns in the integers obtained as values of suitable symmetric polynomials. The simplest example is the following. For every finite coloring of the natural numbers…

Combinatorics · Mathematics 2022-02-16 Mauro Di Nasso

This paper begins by exploring some old and new results about Ramsey numbers and minimum numbers of monochromatic triangles in $2$-colorings of complete graphs, both in the disjoint and non-disjoint cases. We then extend the theory, by…

Combinatorics · Mathematics 2024-04-29 Jamie Bishop , Rebekah Kuss , Benjamin Peet

We show that for all $\ell$ and $\epsilon>0$ there is a constant $c=c(\ell,\epsilon)>0$ such that every $\ell$-coloring of the triples of an $N$-element set contains a subset $S$ of size $c\sqrt{\log N}$ such that at least $1-\epsilon$…

Combinatorics · Mathematics 2009-01-27 David Conlon , Jacob Fox , Benny Sudakov

Given integers $m\le c$ and an exact $c$-coloring of the edges of a complete countably infinite graph (i.e. a coloring that uses exactly $c$ colors), must there be an infinite subgraph that is exactly $m$-colored? Using the Infinite Ramsey…

Combinatorics · Mathematics 2025-12-05 Žarko Ranđelović

A $\delta$-colouring of the point set of a block design is said to be {\em weak} if no block is monochromatic. The {\em chromatic number} $\chi(S)$ of a block design $S$ is the smallest integer $\delta$ such that $S$ has a weak…

Combinatorics · Mathematics 2025-04-17 Andrea C. Burgess , Nicholas J. Cavenagh , Peter Danziger , David A. Pike

We show that, for each real number $\epsilon > 0$ there is an integer $c$ such that, if $M$ is a simple triangle-free binary matroid with $|M| \ge (\tfrac{1}{4} + \epsilon) 2^{r(M)}$, then $M$ has critical number at most $c$. We also give a…

Combinatorics · Mathematics 2016-04-18 Jim Geelen , Peter Nelson

In an $[n] \times [n]$ integer grid, a monochromatic $L$ is any set of points $\{(i, j), (i, j+t), (i+t, j+t)\}$ for some positive integer $t$, where $1 \leq i, j, i+t, j+t \leq n$. In this paper, we investigate the upper bound for the…

Combinatorics · Mathematics 2025-02-10 Isaac Mammel , William Smith , Carl Yerger
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