openAI-math-dataset / lean /OAI /Analysis /IrrationalRotation /Sampling /CircleDigitEndpointLoss.lean
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import OAI.Analysis.IrrationalRotation.Rotation.CircleQuantizedMarginals
import OAI.Analysis.IrrationalRotation.Analysis.EndpointLoss
import OAI.Analysis.IrrationalRotation.Sampling.CircleDigitMarginalLaws
namespace OAI
noncomputable section
open MeasureTheory Filter
open scoped ENNReal Topology
namespace Invariant233.CircleCoupling
variable {θ : ℝ} {p : CircleParameterData}
{hr : ∀ i, 0 < MixedRadix.radices p.q i}
namespace DigitMarginalLaws
lemma sqrt_integral_sq_le (hM : DigitMarginalLaws p hr)
{H : Circle → ℝ} (hH : MemLp H 2 volume)
(hbound : eLpNorm H 2 volume ≤ ENNReal.ofReal marginalBound) :
Real.sqrt (∫ x, H x ^ 2) ≤ marginalBound := by
rw [EndpointLoss.sqrt_integral_sq_eq_toReal_eLpNorm hH]
have ht := ENNReal.toReal_mono ENNReal.ofReal_ne_top hbound
simpa only [ENNReal.toReal_ofReal hM.1.le] using ht
lemma hybrid_preimage_measureReal_le (hM : DigitMarginalLaws p hr)
(hp : CircleParameterLaws θ p)
(j : ℕ) (ε : ℕ → Bool) {s : Set Circle} (hs : MeasurableSet s) :
(law p j).real (hybridPoint p hr ε ⁻¹' s) ≤
marginalBound * Real.sqrt (volume.real s) := by
obtain ⟨H, hH, hnonneg, _hmean, hbound, hlaw⟩ := hM.2 j ε
have hmass := EndpointLoss.withDensity_measureReal_le_sqrt
(volume : Measure Circle) hH hnonneg hs
rw [← hlaw, map_measureReal_apply (measurable_hybridPoint hp hr ε) hs] at hmass
exact hmass.trans (mul_le_mul_of_nonneg_right
(hM.sqrt_integral_sq_le hH hbound) (Real.sqrt_nonneg _))
theorem tendsto_hybrid_sublevel_zero (hM : DigitMarginalLaws p hr)
(hp : CircleParameterLaws θ p)
(ε : ℕ → ℕ → Bool) {r : Circle → ℝ}
(hrmeas : Measurable r) (hrpos : ∀ᵐ x ∂volume, 0 < r x) :
Tendsto (fun j : ℕ => (law p j).real
{ω | r (hybridPoint p hr (ε j) ω) < 1 / (j : ℝ)})
atTop (𝓝 0) := by
have hbase := EndpointLoss.tendsto_measureReal_one_div_sublevel_zero
(volume : Measure Circle) hrmeas hrpos
apply squeeze_zero (fun _ => measureReal_nonneg)
(fun j => hM.hybrid_preimage_measureReal_le hp j (ε j)
(measurableSet_lt hrmeas measurable_const))
simpa only [Function.comp_apply, Real.sqrt_zero, mul_zero] using
tendsto_const_nhds.mul (Real.continuous_sqrt.continuousAt.tendsto.comp hbase)
theorem tendsto_endpoint_bad_union_zero (hM : DigitMarginalLaws p hr)
(hp : CircleParameterLaws θ p)
{r : Circle → ℝ} (hrmeas : Measurable r)
(hrinterior : ∀ᵐ x ∂volume, 0 < r x ∧ r x < 1) :
Tendsto (fun j : ℕ => (law p j).real
({ω | r (point p hr false ω) < 1 / (j : ℝ)} ∪
{ω | 1 - r (point p hr true ω) < 1 / (j : ℝ)}))
atTop (𝓝 0) := by
have hleft := hM.tendsto_hybrid_sublevel_zero hp (fun _ _ => false)
hrmeas (hrinterior.mono fun _ hx => hx.1)
have hright := hM.tendsto_hybrid_sublevel_zero hp (fun _ _ => true)
(measurable_const.sub hrmeas)
(hrinterior.mono fun _ hx => sub_pos.mpr hx.2)
apply squeeze_zero (fun _ => measureReal_nonneg)
(fun _ => measureReal_union_le _ _)
simpa only [hybridPoint_const, Pi.sub_apply, zero_add] using hleft.add hright
end DigitMarginalLaws
theorem tendsto_endpoint_bad_union_zero_of_parameterLaws
(hp : CircleParameterLaws θ p)
(hr : ∀ i, 0 < MixedRadix.radices p.q i)
{r : Circle → ℝ} (hrmeas : Measurable r)
(hrinterior : ∀ᵐ x ∂volume, 0 < r x ∧ r x < 1) :
Tendsto (fun j : ℕ => (law p j).real
({ω | r (point p hr false ω) < 1 / (j : ℝ)} ∪
{ω | 1 - r (point p hr true ω) < 1 / (j : ℝ)}))
atTop (𝓝 0) :=
(digitMarginalLaws hp hr).tendsto_endpoint_bad_union_zero hp hrmeas hrinterior
end Invariant233.CircleCoupling
end
end OAI