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.
The Jordan–Hölder theorem for groups
Statement
If a group has two composition series, then the series have the same length and their composition factors agree up to isomorphism and permutation.
Facts & Assumptions
Given: Two composition series of the same group .
A composition series is a strictly descending subnormal series with simple factors (Composition series, composition factors, and composition length).
Any two finite subnormal series of a group have equivalent refinements (The Schreier refinement theorem).
For , the maps and inverse image under give inverse inclusion-preserving bijections between subgroups above and subgroups of , and they preserve normality (Correspondence theorem: subgroups of correspond to subgroups of containing , with normality preserved).
Proof
By [L1], the two composition series have equivalent refinements.
A subnormal refinement cannot insert a term strictly between adjacent terms : the first inserted term would satisfy and , so [L2] would make a nontrivial proper normal subgroup of the simple factor .
Therefore each refinement differs from its original composition series only by repeated adjacent terms, and deleting those repetitions recovers the original series.
Equivalence of the refinements now pairs the original nontrivial factors; hence the two series have the same number of factors, and a permutation matches their factors up to isomorphism.
Depends on
Used by
- Two composition series of C₁₂ have the same factors in different orders Example
- Composition factors determine the finite group False statement
- The composition factors determine a finite group up to isomorphism False statement
- Simple groups as composition factors Remark
- The published abelian-group composition-series development is the instance Remark
- A finite group is solvable if and only if all its composition factors are cyclic of prime order Theorem
Dependency tree · two levels
12 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
- J. S. Milne, Group Theory, Chapter 6 (standard reference, not scraped)
- K. Conrad, Subgroup Series I (standard reference, not scraped)
- K. Igusa, Notes on Jordan-Hölder, section 5 (standard reference, not scraped)