Turbulence, amalgamation, and generic automorphisms of homogeneous structures
نویسندگان
چکیده
منابع مشابه
Turbulence, Amalgamation, and Generic Automorphisms of Homogeneous Structures
We study topological properties of conjugacy classes in Polish groups, with emphasis on automorphism groups of homogeneous countable structures. We first consider the existence of dense conjugacy classes (the topological Rokhlin property). We then characterize when an automorphism group admits a comeager conjugacy class (answering a question of Truss) and apply this to show that the homeomorphi...
متن کاملSe p 20 04 Turbulence , amalgamation and generic automorphisms of homogeneous structures
(A) We study in this paper topological properties of conjugacy classes in Polish groups. There are two questions which we are particularly interested in. First, does a Polish group G have a dense conjugacy class? This is equivalent (see, e.g., Kechris [95, 8.47]) to the following generic ergodicity property of G: Every conjugacy invariant subset A ⊆ G with the Baire property (e.g., a Borel set)...
متن کاملct 2 00 4 Turbulence , amalgamation and generic automorphisms of homogeneous structures
We study topological properties of conjugacy classes in Polish groups, with emphasis on automorphism groups of homogeneous countable structures. We first consider the existence of dense conjugacy classes (the topological Rokhlin property). We then characterize when an automorphism group admits a comeager conjugacy class (answering a question of Truss) and apply this to show that the homeomorphi...
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We prove that each ∀1 free amalgamation class K over a finite relational language L admits a countable generic structure M isometrically embedding all countable structures in K relative to a fixed metric. We expand L by infinitely many binary predicates expressing distance, and prove that the resulting expansion of K has a model companion axiomatized by the first-order theory of M . The model c...
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Let L be a finite relational language and α = (αR : R ∈ L) a tuple with 0 < αR ≤ 1 for each R ∈ L. Consider a dimension function δα(A) = |A| − ∑
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ژورنال
عنوان ژورنال: Proceedings of the London Mathematical Society
سال: 2006
ISSN: 0024-6115
DOI: 10.1112/plms/pdl007