A permutation group acting transitively on certain collections of models
Abstract
It is shown, from $σ$-centered Martin's Axiom, that there exists a proper dense subgroup of the symmetric group on a countably infinite set whose natural action on sufficiently flexible relational structures is transitive. This allows us to give consistent positive answers to some questions of Peter M. Neumann from the 1980s.
Fields of Study & Subjects
Advanced Topology and Set Theory
Advanced Operator Algebra Research
Homotopy and Cohomology in Algebraic Topology
Publication details
- Journal / source
- European Journal of Combinatorics
- Volume
- 137
- Pages
- 104415–104415
- Publication date
- 25 June 2026
- Language
- EN