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Related papers: Structural Ramsey Theory and the Extension Propert…

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We show that every free amalgamation class of finite structures with relations and (symmetric) partial functions is a Ramsey class when enriched by a free linear ordering of vertices. This is a common strengthening of the…

Combinatorics · Mathematics 2021-07-06 David M. Evans , Jan Hubička , Jaroslav Nešetřil

We prove that the class of finite two-graphs has the extension property for partial automorphisms (EPPA, or Hrushovski property), thereby answering a question of Macpherson. In other words, we show that the class of graphs has the extension…

Combinatorics · Mathematics 2021-02-24 David Evans , Jan Hubička , Matěj Konečný , Jaroslav Nešetřil

We present a proof of the extension property for partial automorphisms (EPPA) for classes of finite $n$-partite tournaments for $n \in \{2,3,\ldots,\omega\}$, and for the class of finite semigeneric tournaments. We also prove that the…

Combinatorics · Mathematics 2025-10-01 Jan Hubička , Colin Jahel , Matěj Konečný , Marcin Sabok

Ramsey theory looks for regularities in large objects. Model theory studies algebraic structures as models of theories. The structural Ramsey theory combines these two fields and is concerned with Ramsey-type questions about certain…

Combinatorics · Mathematics 2018-05-22 Matěj Konečný

It has become obvious in the recent development that the structural Ramsey property is a categorical property: it depends not only on the choice of objects, but also on the choice of morphisms involved. In this paper we explicitely put the…

Category Theory · Mathematics 2015-11-25 Dragan Masulovic , Lynn Scow

We investigate Ramsey expansions, the coherent extension property for partial isometries (EPPA), and the existence of a stationary independence relation for all classes of metrically homogeneous graphs from Cherlin's catalogue. We show…

In this paper we prove a general theorem showing the extension property for partial automorphisms (EPPA, also called the Hrushovski property) for classes of structures containing relations and unary functions, optionally equipped with a…

Combinatorics · Mathematics 2022-01-25 Jan Hubička , Matěj Konečný , Jaroslav Nešetřil

We prove that for every $n\geq 2$ the class of all finite $n$-partite tournaments (orientations of complete $n$-partite graphs) has the extension property for partial automorphisms, that is, for every finite $n$-partite tournament $G$ there…

Combinatorics · Mathematics 2019-03-19 Jan Hubička , Colin Jahel , Matěj Konečný , Marcin Sabok

We prove EPPA (extension property for partial automorphisms) for all antipodal classes from Cherlin's list of metrically homogeneous graphs, thereby answering a question of Aranda et al. This paper should be seen as the first application of…

Combinatorics · Mathematics 2021-06-03 Matěj Konečný

In recent years, there has been much progress in the field of structural Ramsey theory, in particular in the study of big Ramsey degrees. In all known examples of infinite structures with finite big Ramsey degrees, there is in fact a single…

Logic · Mathematics 2025-10-01 Jan Hubička , Andy Zucker

The structural Ramsey theory is a field on the boundary of combinatorics and model theory with deep connections to topological dynamics. Most of the known Ramsey classes in finite binary symmetric relational language can be shown to be…

Combinatorics · Mathematics 2019-08-13 Matěj Konečný

Classical Ramsey theory has successfully extended to relational structures, yielding a wealth of results that have profoundly influenced other areas of mathematics. Interestingly, the same development has not occurred in the case of dual…

Combinatorics · Mathematics 2025-07-02 Aleksa Džuklevski , Dragan Mašulović

We survey some recent results in Ramsey theory. We indicate their connections with topological dynamics. On the foundational side, we describe an abstract approach to finite Ramsey theory. We give one new application of the abstract…

Logic · Mathematics 2015-02-17 Sławomir Solecki

We prove that certain classes of metrically homogeneous graphs omitting triangles of odd short perimeter as well as triangles of long perimeter have the extension property for partial automorphisms and we describe their Ramsey expansions.

In the parlance of relational structures, the Finite Ramsey Theorem states that the class of all finite chains has the Ramsey property. A classical result of J. Ne\v{s}et\v{r}il and V. R\"{o}dl claims that the class of all finite posets…

Combinatorics · Mathematics 2019-04-09 Nemanja Draganić , Dragan Mašulović

We consider finitary approximations of the (embedding) Ramsey property. Using a class of homogeneous reducts of random ordered hypergraphs, we prove that these properties form a strict hierarchy. We also show that every class of finite…

Combinatorics · Mathematics 2023-07-28 Nadav Meir , Aris Papadopoulos

We prove that finite partial orders with a linear extension form a Ramsey class. Our proof is based on the fact that class of acyclic graphs has the Ramsey property and uses the partite construction.

Combinatorics · Mathematics 2017-03-03 Jaroslav Nešetřil , Vojtěch Rödl

In the 1970s, structural Ramsey theory emerged as a new branch of combinatorics. This development came with the isolation of the concepts of the $\mathbf{A}$-Ramsey property and Ramsey class. Following the influential…

Combinatorics · Mathematics 2025-11-03 Jan Hubička , Matěj Konečný

We discuss the externally definable Ramsey property, a weakening of the Ramsey property for ultrahomogeneous structures, where the only colourings considered are those that are externally definable: that is, definable with parameters in an…

Logic · Mathematics 2025-10-20 Nadav Meir , Rob Sullivan

Almost any reasonable class of finite relational structures has the Ramsey property or a precompact Ramsey expansion. In contrast to that, the list of classes of finite algebras with the precompact Ramsey expansion is surprisingly short. In…

Combinatorics · Mathematics 2023-03-13 Dragan Masulovic
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