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Related papers: Selective but not Ramsey

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Category theory provides a means through which many far-ranging fields of mathematics can be related by their similar structure. In a paper by Robinson [2], this interconnectivity afforded by categorical perspectives allowed for the…

Algebraic Topology · Mathematics 2020-12-03 Karthik Boyareddygari

We develop a transfer principle of structural Ramsey theory from finite structures to ultraproducts. We show that under certain mild conditions, when a class of finite structures has finite small Ramsey degrees, under the (Generalized)…

Logic · Mathematics 2025-12-03 Dana Bartošová , Mirna Džamonja , Rehana Patel , Lynn Scow

A set of points $S$ in Euclidean space $\mathbb{R}^d$ is called \textit{Ramsey} if any finite partition of $\mathbb{R}^{\infty}$ yields a monochromatic copy of $S$. While characterization of Ramsey set remains a major open problem in the…

Combinatorics · Mathematics 2025-08-11 Vojtěch Rödl , Marcelo Sales

In this paper, we shed new light on the Flexible Atom Conjecture. We first give finite representation results for relation algebras $33_{37}, 35_{37}$, $77_{83}$, $78_{83}$, $80_{83}$, $82_{83}$, $83_{83}$, $1310_{1316}$, $1313_{1316}$,…

Logic · Mathematics 2023-07-27 Jeremy F. Alm , Michael Levet

Carlson introduced the notion of a Ramsey space as a generalization to the Ellentuck space. When a Ramsey space is induced by an algebra, Carlson suggested a study of its purely combinatorial version now called Ramsey algebra. Some basic…

Logic · Mathematics 2017-03-31 Zu Yao Teoh , Wen Chean Teh

The celebrated theorem of Kechris, Pestov and Todor\v{c}evi\'c connecting structural Ramsey theory with topological dynamics has as a consequence that the Fra\"{\i}ss\'e limit of a Ramsey class of non-trivial finite relational structures…

Logic · Mathematics 2025-12-08 Peter J. Cameron , Siavash Lashkarighouchani

In this paper we show that a countable structure admitting a finite monomorphic decomposition has finite big Ramsey degrees if and only if so does every monomorphic part in its minimal monomorphic decomposition. The necessary prerequisite…

Logic · Mathematics 2026-05-21 Dragan Mašulović , Veljko Toljić

Extending a result of K. Milliken \cite{Mi2}, in this paper we prove a Ramsey classification result for equivalence relations defined on uniform families of finite strong subtrees of a finite sequence $(U_i)_{i\in d}$ of fixed trees $U_i$,…

Logic · Mathematics 2014-10-21 Dimitris Vlitas

We use ergodic theoretic tools to solve a classical problem in geometric Ramsey theory. Let E be a measurable subset of R^m, with positive upper density. Let V={0,v_1,...,v_k} be a subset of R^m. We show that for r large enough, we can find…

Dynamical Systems · Mathematics 2012-01-04 Tamar Ziegler

We state the Ramsey property of classes of ordered structures with closures and given local properties. This generalises many old and new results: the Ne\v{s}et\v{r}il-R\"{o}dl Theorem, the author's Ramsey lift of bowtie-free graphs as well…

Combinatorics · Mathematics 2017-06-07 Jan Hubička , Jaroslav Nešetřil

We show that Ramsey theory, a domain presently conceived to guarantee the existence of large homogeneous sets for partitions on k-tuples of words (for every natural number k) over a finite alphabet, can be extended to one for partitions on…

Combinatorics · Mathematics 2007-05-23 V. Farmaki , S. Negrepontis

This article is a fundamental study in computable analysis. In the framework of Type-2 effectivity, TTE, we investigate computability aspects on finite and infinite products of effective topological spaces. For obtaining uniform results we…

Logic in Computer Science · Computer Science 2015-07-01 Robert Rettinger , Klaus Weihrauch

This paper addresses several questions of Feng, Gruenhage, and Shen which arose from Michael's theory of continuous selections from countable spaces. We construct an example of a space which is $L$-selective but not $\mathbb{Q}$-selective…

General Topology · Mathematics 2019-10-24 William Chen-Mertens , Paul J. Szeptycki

For the importance of differentiation theorems in metric spaces (starting with Pansu Rademacher type theorem in Carnot groups) and relations with rigidity of embeddings see the section 1.2 in Cheeger and Kleiner paper arXiv:math/0611954 and…

Metric Geometry · Mathematics 2009-11-25 Marius Buliga

Ramsey algebras are algebras that induce Ramsey spaces, which are generalizations of the Ellentuck space and Milliken's space. Previous work suggests a possible local version of Ramsey algebras induced by infinite sequences. Hence, we…

Logic · Mathematics 2017-04-13 Wen Chean Teh , Zu Yao Teoh

In this paper we further study links between concentration of measure in topological transformation groups, existence of fixed points, and Ramsey-type theorems for metric spaces. We prove that whenever the group $\Iso(\U)$ of isometries of…

Functional Analysis · Mathematics 2007-09-03 Vladimir Pestov

We extend the result of arXiv:0911.5414 about embedding of ideal-determined algebraic systems into ultraproducts, to arbitrary algebraic systems, and to ultraproducts over $\kappa$-complete ultrafilters. We also discuss the scope of…

Rings and Algebras · Mathematics 2016-09-14 Pasha Zusmanovich

We show that, under suitably general formulations, covering properties, accumulation properties and filter convergence are all equivalent notions. This general correspondence is exemplified in the study of products. Let $X$ be a product of…

General Topology · Mathematics 2023-03-28 Paolo Lipparini

We study the obstructions to coarse universality in separable dual Banach spaces. We prove coarse non-universality of several classes of dual spaces, including those with conditional spreading bases, as well as generalized James and James…

Functional Analysis · Mathematics 2025-12-08 Stephen Jackson , Cory Krause , Bunyamin Sari

An ultrafilter $p$ on $\omega$ is said to be discrete if, given any function $f\colon \omega \to X$ to any completely regular Hausdorff space, there is an $A \in p$ such that $f(A)$ is discrete. Basic properties of discrete ultrafilters are…

General Topology · Mathematics 2022-08-18 Anastasiya Groznova , Ol'ga Sipacheva
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