DefinitionDefinition: Literature-sourcedProof: Not applicableSession-authored (Fable 5 assisted)audited 2026-08-27
How statement and proof provenance work
The first chip identifies the source of the statement or construction; the second identifies the source of its local proof or verification.
- Literature-sourced: the exact statement appears in a cited source; only wording and notation differ.
- AI-adapted: a semantically identical restatement of literature-sourced material, modulo indexing, notation, and boundary cases adopted by the library.
- AI-generated: a genuinely novel statement formulated by AI, with no source for the claim itself.
These labels describe origin, not correctness: citations and verification chips remain separate evidence.
Affine, almost simple, diagonal, product action, and twisted wreath types
Definition
For a finite primitive permutation group , the five coarse O'Nan-Scott types used on this page are:
- Affine type: the socle is the unique minimal normal subgroup, it is abelian and regular, and A unique abelian minimal normal subgroup gives affine type identifies it with a finite vector space.
- Almost simple type: the socle is a nonabelian simple group and the whole group lies between that socle and its full automorphism group in the sense of Almost simple finite groups.
- Diagonal type: the socle is a direct product , with , of isomorphic nonabelian simple groups, and the action is the standard diagonal action on a coset space of a diagonal subgroup.
- Product action type: after identifying with for some , there is a primitive group on of almost simple or diagonal type, with , such that where is the transitive group induced by on the coordinates and the wreath product has its product action. If , its product action is
- Twisted wreath type: the socle is again regular and nonabelian, but the regular action is built from a twisted wreath product rather than from an abelian vector-space action.
Depends on
Used by
- A transitive imprimitive action can have a nontransitive minimal normal subgroup Counterexample
- A primitive product-action wreath product Example
- A simple diagonal action Example
- The natural action of AGL(1,p) is affine type Example
- The natural action of Aₙ is almost simple type Example
- Product-action wreath products are primitive under the standard hypotheses Lemma
- This page uses the coarse five-type O'Nan-Scott convention Remark
- The O'Nan-Scott classification of finite primitive groups Theorem
Dependency tree · two levels
18 results within two dependency steps of this one, each drawn at its shortest distance from it. An arrow runs from a result to what uses it, so the chart reads left to right and ends at this result, which carries a heavier outline. Every node is a link to that result. Click elsewhere on the chart to enlarge it.
Sources
- Leonard H. Soicher, Primitive permutation groups (standard reference, not scraped)
- M. W. Liebeck, C. E. Praeger, and J. Saxl, On the O'Nan-Scott Theorem for Finite Primitive Permutation Groups (standard reference, not scraped)