import Mathlib import OAI.GroupTheory.SimpleAmenable.Configurations.FiveTrackGeneration namespace OAI section section open scoped symmDiff namespace SimpleAmenable open scoped commutatorElement open scoped commutatorElement section ConditionalTranslationStabilizers variable {a m : ℕ} theorem trackTranslation_conditional_commute (U : polygonAlgebra a) (σ : Equiv.Perm (Fin m)) (d : Fin m → CutRing × CutRing) (hd : ∀ i, σ i ≠ i → d i = 0) : Commute (trackTranslation d) (conditionalHom U σ) := by have he := conditional_translation_conjugate U σ d 0 hd have hU : (⟨translate a (-0) ⁻¹' U.val,polygon_preimage_translate (-0) U.property⟩ : polygonAlgebra a) = U := by apply Subtype.ext ext p simp only [Set.mem_preimage,neg_zero,translate_zero] rw [hU] at he have hx := congrArg (fun z => z * trackTranslation d) he change _*_ = _*_ simpa only [mul_assoc,inv_mul_cancel,mul_one] using hx.symm theorem conditional_conjugation_support (U : polygonAlgebra a) (σ : Equiv.Perm (Fin m)) (d e : Fin m → CutRing × CutRing) (hde : ∀ i, σ i ≠ i → d i = e i) : trackTranslation d * conditionalHom U σ * (trackTranslation d)⁻¹ = trackTranslation e * conditionalHom U σ * (trackTranslation e)⁻¹ := by have hc := trackTranslation_conditional_commute U σ (d-e) (by intro i hi change d i - e i = 0 rw [hde i hi,sub_self]) rw [trackTranslation_sub] at hc have hcomm : Commute (trackTranslation (a := a) d) (trackTranslation e) := by change _*_ = _*_ rw [← trackTranslation_add,← trackTranslation_add,add_comm d e] have he := congrArg (fun z => trackTranslation e * z * (trackTranslation d)⁻¹) hc.eq rw [hcomm.inv_right.eq] at he have hh : trackTranslation e * ((trackTranslation e)⁻¹ * trackTranslation d * conditionalHom U σ) * (trackTranslation d)⁻¹ = trackTranslation d * conditionalHom U σ * (trackTranslation d)⁻¹ := by group rw [hh] at he convert he using 1; group end ConditionalTranslationStabilizers end SimpleAmenable end end end OAI