S-homogeneity and automorphism groups
| Autor: | Michael C. Laskowski, Elisabeth Bouscaren |
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| Rok vydání: | 1993 |
| Předmět: | |
| Zdroj: | Journal of Symbolic Logic. 58:1302-1322 |
| ISSN: | 1943-5886 0022-4812 |
| DOI: | 10.2307/2275145 |
| Popis: | We consider the question of when, given a subset A of M, the setwise stabilizer of the group of automorphisms induces a closed subgroup on Sym(A). We define s-homogeneity to be the analogue of homogeneity relative to strong embeddings and show that any subset of a countable, s-homogeneous, ω-stable structure induces a closed subgroup and contrast this with a number of negative results. We also show that for ω-stable structures s-homogeneity is preserved under naming countably many constants, but under slightly weaker conditions it can be lost by naming a single point. |
| Databáze: | OpenAIRE |
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