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Related papers: An axiomatic approach to free amalgamation

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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 develop infinite-dimensional Ramsey theory for Fra\"iss\'e limits of finitely constrained free amalgamation classes in finite binary languages. We show that our approach is optimal and in particular, recovers the exact big Ramsey degrees…

Logic · Mathematics 2023-12-27 Natasha Dobrinen , Andy Zucker

We provide a self-contained introduction to the classical theory of universal-homogeneous models (also known as generic structures, rich models, or Fra\"iss\'e limits). In the literature, most treatments restrict consideration to embeddings…

Logic · Mathematics 2010-09-10 Silvia Barbina , Domenico Zambella

We develop a family of simple rank one theories built over quite arbitrary sequences of finite hypergraphs. (This extends an idea from the recent proof that Keisler's order has continuum many classes, however, the construction does not…

Logic · Mathematics 2024-07-24 M. Malliaris , S. Shelah

Let L be a countable elementary language, N be a Fraisse limit. We consider free amalgamation for L-structures where L is arbitrary. If free amalgamation for finitely generated substructures exits in N, then it is a stationary independece…

Logic · Mathematics 2014-06-05 Andreas Baudisch

We define the notions of a free fusion of structures and a weakly stationary independence relation. We apply these notions to prove simplicity for the automorphism groups of order and tournament expansions of homogeneous structures like the…

Group Theory · Mathematics 2021-04-13 Filippo Calderoni , Aleksandra Kwiatkowska , Katrin Tent

We initiate the study of a generalization of Kim-independence, Conant-independence, based on the "strong Kim-dividing" of Kaplan, Ramsey and Shelah. We introduce an axiom on stationary independence relations essentially generalizing the…

Logic · Mathematics 2024-01-26 Scott Mutchnik

For a complete, stable theory $T$ we construct, in a reasonably canonical way, a related stable theory $T^*$ which has higher independent amalgamation properties over the algebraic closure of the empty-set. The theory $T^*$ is an algebraic…

Logic · Mathematics 2018-05-09 David M. Evans , Jonathan Kirby , Tim Zander

Suppose that M is countable, binary, primitive, homogeneous, and simple, and hence 1-based. We prove that the SU-rank of the complete theory of M is~1. It follows that M is a random structure. The conclusion that M is a random structure…

Logic · Mathematics 2016-08-10 Vera Koponen

Let $T$ be a first-order theory. A correspondence is established between internal covers of models of $T$ and definable groupoids within $T$. We also consider amalgamations of independent diagrams of algebraically closed substructures, and…

Logic · Mathematics 2024-07-30 Ehud Hrushovski

We investigate atomicity of free algebras and various forms of amalgamation for BL and MV algebras, and also Heyting algebras, though the latter algebras may not be linearly ordered, so strictly speaking their corresponding intuitionistic…

Logic · Mathematics 2013-04-05 Tarek Sayed Ahmed

We prove that the group of tame automorphisms of a free Lie algebra (as well as of a free anticommutative algebra) rank 3 over an arbitrary integral domain has the structure of an amalgamated free product. We construct an example of a wild…

Rings and Algebras · Mathematics 2020-01-03 Alibek Alimbaev , Ruslan Nauryzbaev , Ualbai Umirbaev

We initiate a systematic study of the class of theories without the tree property of the second kind - NTP2. Most importantly, we show: the burden is "sub-multiplicative" in arbitrary theories (in particular, if a theory has TP2 then there…

Logic · Mathematics 2013-08-15 Artem Chernikov

We prove that for every simple theory $T$ (or even simple thick compact abstract theory) there is a (unique) compact abstract theory $T^\fP$ whose saturated models are the lovely pairs of $T$. Independence-theoretic results that were proved…

Logic · Mathematics 2009-02-05 Itaï Ben Yaacov

In this paper we study fundamental model-theoretic questions for free associative algebras, namely, first-order classification, decidability of the first-order theory, and definability of the set of free bases. We show that two free…

Logic · Mathematics 2018-08-16 Olga Kharlampovich , Alexei Myasnikov

We show that the theory of the free group -- and more generally the theory of any torsion-free hyperbolic group -- is $n$-ample for any $n\geq 1$. We give also an explicit description of the imaginary algebraic closure in free groups.

Group Theory · Mathematics 2012-05-15 Abderezak Ould Houcine , Katrin Tent

We study in this paper some connections between the Fraisse theory of amalgamation classes and ultrahomogeneous structures, Ramsey theory, and topological dynamics of automorphism groups of countable structures.

Logic · Mathematics 2007-09-03 A. S. Kechris , V. G. Pestov , S. Todorcevic

We study the existence of automatic presentations for various algebraic structures. An automatic presentation of a structure is a description of the universe of the structure by a regular set of words, and the interpretation of the…

Discrete Mathematics · Computer Science 2017-01-11 Bakhadyr Khoussainov , Andre Nies , Sasha Rubin , Frank Stephan

We give strengthened versions of the Herwig-Lascar and Hodkinson-Otto extension theorems for partial automorphisms of finite structures. Such strengthenings yield several combinatorial and group-theoretic consequences for homogeneous…

Logic · Mathematics 2019-04-17 Daoud Siniora , Sławomir Solecki

We extend the relation between random matrices and free probability theory from the level of expectations to the level of all correlation functions (which are classical cumulants of traces of products of the matrices). We introduce the…

Operator Algebras · Mathematics 2007-06-13 Benoit Collins , James A. Mingo , Piotr Sniady , Roland Speicher
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