Abstract
Let G be a finitely generated regular branch group acting by automorphisms on a regular rooted tree T. It is well-known that stabilizers of infinite rays in T (aka parabolic subgroups) are weakly maximal subgroups in G, that is, maximal among subgroups of infinite index. We show that, given a finite subgroup Q≤. G, G possesses uncountably many automorphism equivalence classes of weakly maximal subgroups containing Q. In particular, for Grigorchuk-Gupta-Sidki type groups this implies that they have uncountably many automorphism equivalence classes of weakly maximal subgroups that are not parabolic.
Original language | English |
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Pages (from-to) | 347-357 |
Number of pages | 11 |
Journal | Journal of Algebra |
Volume | 455 |
DOIs | |
Publication status | Published - 1 Jun 2016 |
Externally published | Yes |
Keywords
- Branch groups
- Grigorchuk group
- Parabolic subgroups
- Primary
- Secondary
- Weakly maximal subgroups