Automorphism groups of countable highly homogeneous partially ordered sets (Q1320983)
From MaRDI portal
| This is the item page for this Wikibase entity, intended for internal use and editing purposes. Please use this page instead for the normal view: Automorphism groups of countable highly homogeneous partially ordered sets |
scientific article; zbMATH DE number 561285
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Automorphism groups of countable highly homogeneous partially ordered sets |
scientific article; zbMATH DE number 561285 |
Statements
Automorphism groups of countable highly homogeneous partially ordered sets (English)
0 references
21 July 1994
0 references
We prove Theorem 1. The automorphism group \(G\) of the countable universal poset is simple. Actually, if \(g\in G\) and \(g \neq 1\), then every element of \(G\) can be written in the form \(\prod^ 8_{j = 1}(h^{-1}_{2j-1} gh_{2j-1} \cdot h^{-1}_{2j} g^{-1} h_{2j})\), for some \(h_ 1,\dots,h_{16} \in G\). Theorem 2. If \((\Omega,\leq)\) is a countable highly homogeneous poset, then ``almost all'' finitely generated subgroups of \(\text{Aut}(\Omega,\leq)\) are free. (``Almost all'' is in the Baire Category sense).
0 references
automorphism group
0 references
countable universal poset
0 references
highly homogeneous poset
0 references
finitely generated subgroups
0 references
0 references