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For each $n\geq 2$, we show that the class of all finite $n$-dimensional partial orders, when expanded with $n$ linear orders which realize the partial order, forms a Fra\"iss\'e class and identify its Fra\"iss\'e limit…

Combinatorics · Mathematics 2025-01-16 Iian B. Smythe , Mithuna Threz , Max Wiebe

We show that the Hrushovski-\fraisse limit of certain classes of trees lead to strictly superstable theories of various U-ranks. In fact, for each $ \alpha\in\omega+1\backslash\{0\} $ we introduce a strictly superstable theory of U-rank $…

Logic · Mathematics 2025-10-16 Ali N. Valizadeh , Massoud Pourmahdian

In this paper, we study uniform rooted plane trees with given degree sequence. We show, under some natural hypotheses on the degree sequence, that these trees converge toward the so-called Inhomogeneous Continuum Random Tree after…

Probability · Mathematics 2025-11-24 Gabriel Berzunza Ojeda , Cecilia Holmgren , Paul Thévenin

Big Ramsey degrees of finite structures are usually considered with respect to a Fra\"{i} ss\'e limit. Building mainly on the work of Devlin, Sauer, Laflamme and Van Th\'e, in this paper we consider structures which are not Fra\"{i} ss\'e…

Combinatorics · Mathematics 2018-07-06 Dragan Masulovic

I will give a presentation of an abstract approach to finite Ramsey theory found in an earlier paper of mine. I will prove from it a common generalization of Deuber's Ramsey theorem for regular trees and a recent Ramsey theorem of Jasinski…

Combinatorics · Mathematics 2012-10-03 Slawomir Solecki

We develop the theory of approximate Fra\"{i}ss\'{e} limits in the context of categories enriched over metric spaces. Among applications, we construct a generic projection on the Gurarii space and we present a simpler proof of a…

Category Theory · Mathematics 2013-11-01 Wiesław Kubiś

This article gives a summary of the author's Ph.D. dissertation (arXiv:1609.06297). In addition to an overview of notions and results, it also provides sketches of various proofs and simplified presentations of certain abstract results of…

Logic in Computer Science · Computer Science 2018-11-05 Abhisekh Sankaran

We establish a cutting lemma for definable families of sets in distal structures, as well as the optimality of the distal cell decomposition for definable families of sets on the plane in $o$-minimal expansions of fields. Using it, we…

Logic · Mathematics 2020-02-28 Artem Chernikov , David Galvin , Sergei Starchenko

We develop a theory of \emph{Katetov functors} which provide a uniform way of constructing Fraisse limits. Among applications, we present short proofs and improvements of several recent results on the structure of the group of automorphisms…

Logic · Mathematics 2015-07-21 Wiesław Kubiś , Dragan Mašulović

Quasi-trees generalize trees in that the unique "path" between two nodes may be infinite and have any countable order type. They are used to define the rank-width of a countable graph in such a way that it is equal to the least upper-bound…

Logic in Computer Science · Computer Science 2023-06-22 Bruno Courcelle

We build a collection of topological Ramsey spaces of trees giving rise to universal inverse limit structures,extending Zheng's work for the profinite graph to the setting of Fra\"{\i}ss\'{e} classes of finite ordered binary relational…

Combinatorics · Mathematics 2022-05-20 Natasha Dobrinen , Kaiyun Wang

The general theory developed by Ben Yaacov for metric structures provides Fra\"iss\'e limits which are approximately ultrahomogeneous. We show here that this result can be strengthened in the case of relational metric structures. We give an…

Logic · Mathematics 2019-08-13 David Bryant , André Nies , Paul Tupper

We prove that the group of automorphisms of the generic meet-tree expansion of an infinite non-unary free Fra\"{\i}ss\'{e} limit over a finite relational language is simple. As a prototypical case, the group of automorphism of the Rado…

Logic · Mathematics 2025-10-01 Itay Kaplan , Binyamin Riahi , Arturo Rodriguez Fanlo

We compare two different notions of generic expansions of countable saturated structures. One kind of genericity is related to model-companions and to amalgamation constructions \'a la Hrushovski-Fra\"iss\'e. Another notion of generic…

Logic · Mathematics 2015-11-03 Silvia Barbina , Domenico Zambella

We study a model of random $\mathcal{R}$-enriched trees that is based on weights on the $\mathcal{R}$-structures and allows for a unified treatment of a large family of random discrete structures. We establish distributional limits…

Probability · Mathematics 2018-12-12 Benedikt Stufler

Local convergence of bounded degree graphs was introduced by Benjamini and Schramm. This result was extended further by Lyons to bounded average degree graphs. In this paper, we study the convergence of a random tree sequence where the…

Probability · Mathematics 2014-02-04 Attila Deák

We show that the WZW fusion rings at finite levels form a projective system with respect to the partial ordering provided by divisibility of the height, i.e. the level shifted by a constant. From this projective system we obtain WZW fusion…

High Energy Physics - Theory · Physics 2009-10-30 J"urgen Fuchs , Christoph Schweigert

We give a characterizations of toposes which admit a generating family of objects which are internally cardinal finite (i.e. Kuratowski finite and decidable) in terms of "topological" conditions. The central result is that, constructively,…

Category Theory · Mathematics 2016-04-06 Simon Henry

Homeomorphism groups of generalized Wa\.zewski dendrites act on the infinite countable set of branch points of the dendrite and thus have a nice Polish topology. In this paper, we study them in the light of this Polish topology. The group…

Group Theory · Mathematics 2025-02-11 Bruno Duchesne

We study the topological invariant $\phi$ of Kwieci\'nski and Tworzewski, particularly beyond the case of mappings with smooth targets. We derive a lower bound for $\phi$ of a general mapping, which is similarly effective as the upper bound…

Complex Variables · Mathematics 2016-12-19 Hadi Seyedinejad