FenchelNielsenZomorrodian/Discrete/FiniteIndex/SmoothQuotientData.lean
1import FenchelNielsenZomorrodian.Discrete.FiniteIndex.Smooth
2import FenchelNielsenZomorrodian.Discrete.Torsion.CompactFiniteOrder
4/-
5PUBLIC_PAGE_SNAPSHOT
6generated_at: 2026-05-27T09:47:29+09:00
7lean_source: lean4/FenchelNielsenZomorrodian/Discrete/FiniteIndex/SmoothQuotientData.lean
8translation_root: data/translation
9purpose: identifies the local data snapshot used to build pages/
10placement: after imports, never before imports
11-/
12/-!
15Abbreviates the generic smooth quotient package for compact Fuchsian presentations and records the
16source-subgroup existence theorem consumed by the profinite Fenchel-Nielsen bridge.
17-/
19namespace FenchelNielsen
21/-!
22# Smooth quotient data for compact Fuchsian presentations
24The compact specialization keeps only the abbreviation and the source-subgroup existence theorem
26available from `SmoothQuotientData` and are no longer repeated here.
27-/
30 (σ : FuchsianSignature) (m : ℕ) :=
33 (Fin σ.numPeriods)
34 σ.periods
35 (ellipticElement σ)
36 m
38namespace FiniteSolvableSmoothQuotientData
40/-- The finite smooth quotient kernel gives the finite-index torsion-free subgroup consumed by the
43 {σ : FuchsianSignature} {m : ℕ}
44 (D : FiniteSolvableSmoothQuotientData σ m) :
45 ∃ L : Subgroup (FuchsianPresentedGroup σ),
46 L.FiniteIndex ∧ IsTorsionFreeGroup L ∧
48 SmoothQuotientData.sourceSubgroup_exists_of_finiteOrderClassification
49 D
50 (fun i _n hdiv => ellipticElement_zpow_eq_one_of_period_int_dvd σ i hdiv)
55end FenchelNielsen