Automorphisms of the Rado meet-tree

We prove that the group of automorphisms of the generic meet-tree expansion of an infinite non-unary free Fraïssé limit over a finite relational language is simple. As a prototypical case, the group of automorphisms of the Rado meet-tree (i.e. the Fraïssé limit of finite graphs which are also meet-t...

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Detalles Bibliográficos
Autores: Kaplan, Itay, Riahi, Binyamin, Rodríguez Fanlo, Arturo
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universidad Autónoma de Madrid
Repositorio:Biblos-e Archivo. Repositorio Institucional de la UAM
Idioma:inglés
OAI Identifier:oai:repositorio.uam.es:10486/719635
Acceso en línea:http://hdl.handle.net/10486/719635
https://dx.doi.org/10.1016/j.jalgebra.2025.03.020
Access Level:acceso abierto
Palabra clave:Automorphism groups
Fraisse limits
Homogeneous structures
Meet-trees
Oligomorphic permutation groups
Semilattices
Simple groups
Stationary independence relations
Matemáticas
Descripción
Sumario:We prove that the group of automorphisms of the generic meet-tree expansion of an infinite non-unary free Fraïssé limit over a finite relational language is simple. As a prototypical case, the group of automorphisms of the Rado meet-tree (i.e. the Fraïssé limit of finite graphs which are also meet-trees) is simple