Sparse graphs and the fixed points on type spaces property

Fuente: arXiv
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Main Author: Sullivan, Rob
Format: Preprint
Published: 2023
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author Sullivan, Rob
author_facet Sullivan, Rob
contents We examine the topological dynamics of the automorphism groups of omega-categorical sparse graphs resulting from Hrushovski constructions. Specifically, we consider the fixed points on type spaces property, which a structure M has if, for each positive integer n, every Aut(M)-subflow of the space of n-types has a fixed point. Extending a result of Evans, Hubicka and Nesetril, we show that there exists an omega-categorical structure M, resulting from a Hrushovski construction, such that no omega-categorical expansion of M has the fixed points on type spaces property.
format Preprint
id arxiv_https___arxiv_org_abs_2309_06829
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Sparse graphs and the fixed points on type spaces property
Sullivan, Rob
Logic
03C15, 37B05, 20B27, 05C55, 05D10
We examine the topological dynamics of the automorphism groups of omega-categorical sparse graphs resulting from Hrushovski constructions. Specifically, we consider the fixed points on type spaces property, which a structure M has if, for each positive integer n, every Aut(M)-subflow of the space of n-types has a fixed point. Extending a result of Evans, Hubicka and Nesetril, we show that there exists an omega-categorical structure M, resulting from a Hrushovski construction, such that no omega-categorical expansion of M has the fixed points on type spaces property.
title Sparse graphs and the fixed points on type spaces property
topic Logic
03C15, 37B05, 20B27, 05C55, 05D10
url https://arxiv.org/abs/2309.06829