openAI-math-dataset / lean /OAI /Analysis /IrrationalRotation /Rotation /CircleOrderedSharpness.lean
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import OAI.Analysis.IrrationalRotation.Rotation.CircleOrderedHaarRigidity
import OAI.Analysis.IrrationalRotation.Analysis.RationalGraphTrimming
namespace OAI
noncomputable section
open MeasureTheory Filter
namespace Invariant233.CircleOrderedRigidity
def rationalPeriodGraph (p : CircleParameterData) : Measure (Circle × Circle) :=
circleMeasure.map (fun x : Circle =>
(x, x + (((1 : ℝ) / p.q 1 : ℝ) : Circle)))
theorem measurable_rationalPeriodPair (p : CircleParameterData) :
Measurable (fun x : Circle =>
(x, x + (((1 : ℝ) / p.q 1 : ℝ) : Circle))) := by
fun_prop
theorem rationalPeriodGraph_fst (p : CircleParameterData) :
(rationalPeriodGraph p).map Prod.fst = circleMeasure := by
rw [rationalPeriodGraph, Measure.map_map measurable_fst
(measurable_rationalPeriodPair p)]
exact Measure.map_id
theorem rationalPeriodGraph_snd (p : CircleParameterData) :
(rationalPeriodGraph p).map Prod.snd = circleMeasure := by
rw [rationalPeriodGraph, Measure.map_map measurable_snd
(measurable_rationalPeriodPair p)]
unfold circleMeasure
exact map_add_right_eq_self volume _
theorem rationalPeriodGraph_probability (p : CircleParameterData) :
IsProbabilityMeasure (rationalPeriodGraph p) := by
exact (Measure.isProbabilityMeasure_map_iff
(measurable_rationalPeriodPair p).aemeasurable).2 circleMeasure_probability
theorem first_frequency_gt_one {θ : ℝ} {p : CircleParameterData}
(hp : CircleParameterLaws θ p) : 1 < p.q 1 := by
simpa only [hp.frequency_zero] using hp.frequency_increasing (by omega : 0 < 1)
theorem rationalPeriod_ne_zero {θ : ℝ} {p : CircleParameterData}
(hp : CircleParameterLaws θ p) :
(((1 : ℝ) / p.q 1 : ℝ) : Circle) ≠ 0 := by
have hq : (1 : ℝ) < p.q 1 := by exact_mod_cast first_frequency_gt_one hp
have ht : (1 : ℝ) / p.q 1 ∈ Set.Ico (0 : ℝ) 1 := by
constructor
· positivity
· exact (div_lt_one (by positivity)).2 hq
intro he
have hz := (AddCircle.coe_eq_zero_iff_of_mem_Ico ht).1 he
have hpos : (0 : ℝ) < 1 / p.q 1 := by positivity
exact hpos.ne' hz
theorem rationalPeriodGraph_ae_coordinate_eq {θ : ℝ} {p : CircleParameterData}
(hp : CircleParameterLaws θ p) :
∀ᵐ xy ∂rationalPeriodGraph p, ∀ i : ℕ, 1 ≤ i →
p.coordinate i xy.1 = p.coordinate i xy.2 := by
apply ae_all_iff.2
intro i
by_cases hi : 1 ≤ i
· have hmeas : MeasurableSet {xy : Circle × Circle |
p.coordinate i xy.1 = p.coordinate i xy.2} :=
measurableSet_eq_fun ((p.measurable_coordinate i).comp measurable_fst)
((p.measurable_coordinate i).comp measurable_snd)
have he : ∀ᵐ xy ∂rationalPeriodGraph p,
p.coordinate i xy.1 = p.coordinate i xy.2 := by
apply (ae_map_iff (measurable_rationalPeriodPair p).aemeasurable hmeas).2
exact Filter.Eventually.of_forall fun x => by
simpa using (hp.coordinate_rational_translation hi (1 : ℤ) x).symm
exact he.mono fun _ h _ => h
· exact Filter.Eventually.of_forall fun _ h => (hi h).elim
theorem rationalPeriodGraph_ae_ne {θ : ℝ} {p : CircleParameterData}
(hp : CircleParameterLaws θ p) :
∀ᵐ xy ∂rationalPeriodGraph p, xy.1 ≠ xy.2 := by
apply (ae_map_iff (measurable_rationalPeriodPair p).aemeasurable
(measurableSet_eq_fun measurable_fst measurable_snd).compl).2
exact Filter.Eventually.of_forall fun x h => by
have he : (((1 : ℝ) / p.q 1 : ℝ) : Circle) = 0 := by
exact (add_left_cancel (show x + (((1 : ℝ) / p.q 1 : ℝ) : Circle) = x + 0 by
simpa using h.symm))
exact rationalPeriod_ne_zero hp he
theorem exists_ordered_haar_law_off_diagonal {θ : ℝ} {p : CircleParameterData}
(hp : CircleParameterLaws θ p) :
∃ η : Measure (Circle × Circle), IsProbabilityMeasure η ∧
η.map Prod.fst = circleMeasure ∧ η.map Prod.snd = circleMeasure ∧
(∀ᵐ xy ∂η, ∀ i : ℕ, 1 ≤ i →
p.coordinate i xy.1 ≤ p.coordinate i xy.2) ∧
(∀ᵐ xy ∂η, xy.1 ≠ xy.2) := by
refine ⟨rationalPeriodGraph p, rationalPeriodGraph_probability p,
rationalPeriodGraph_fst p, rationalPeriodGraph_snd p, ?_,
rationalPeriodGraph_ae_ne hp⟩
exact (rationalPeriodGraph_ae_coordinate_eq hp).mono fun _ h i hi => (h i hi).le
end Invariant233.CircleOrderedRigidity
end
end OAI