File size: 7,106 Bytes
f61e547
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
import OAI.Probability.FreeIsing.Ising.CanonicalPosteriorStops

namespace OAI

noncomputable section
open MeasureTheory ProbabilityTheory Filter Set
open scoped NNReal

namespace Problem367.IsingObservationFactor
open IsingObservationInnovation IsingCopyEnergy PosteriorCompensatorStopping

variable {d : ℕ} {beta : ℝ}
variable {μ : Measure (TreeVertex d → IsingSpin)} [IsProbabilityMeasure μ]

def copyResponseDriftDifference (beta : ℝ) (v : TreeVertex d)
    (t : ℝ≥0) (q : Joint d) : ℝ :=
  posterior beta v t q.2.1 * copyResponseEnergy beta v true t q -
    posterior beta v t q.2.2 * copyResponseEnergy beta v false t q

lemma copyResponseDriftDifference_progressive (beta : ℝ) (v : TreeVertex d) :
    IsStronglyProgressive ContinuousCopyBrownian.joinedFiltration
      (copyResponseDriftDifference beta v) := by
  have hl := isStronglyProgressive_infiniteGibbsSpinMean
    ContinuousCopyBrownian.joinedFiltration beta v _
    IsingConditionalCopyBounds.progressive_leftObservation
  have hr := isStronglyProgressive_infiniteGibbsSpinMean
    ContinuousCopyBrownian.joinedFiltration beta v _
    IsingConditionalCopyBounds.progressive_rightObservation
  exact (hl.mul (copyResponseEnergy_progressive beta v true)).sub
    (hr.mul (copyResponseEnergy_progressive beta v false))

lemma copyResponseEnergy_nonneg (beta : ℝ) (v : TreeVertex d) (j : Bool)
    (t : ℝ≥0) (q : Joint d) : 0 ≤ copyResponseEnergy beta v j t q :=
  tsum_nonneg (fun _ => sq_nonneg _)

theorem abs_copyResponseDriftDifference_le (beta : ℝ) (v : TreeVertex d)
    (t : ℝ≥0) (q : Joint d) :
    |copyResponseDriftDifference beta v t q| ≤
      copyResponseEnergy beta v true t q + copyResponseEnergy beta v false t q := by
  have hl : |posterior beta v t q.2.1| ≤ 1 := posterior_norm_le_one beta v t q.2.1
  have hr : |posterior beta v t q.2.2| ≤ 1 := posterior_norm_le_one beta v t q.2.2
  unfold copyResponseDriftDifference
  calc
    _ ≤ |posterior beta v t q.2.1 * copyResponseEnergy beta v true t q| +
        |posterior beta v t q.2.2 * copyResponseEnergy beta v false t q| := abs_sub _ _
    _ = |posterior beta v t q.2.1| * copyResponseEnergy beta v true t q +
        |posterior beta v t q.2.2| * copyResponseEnergy beta v false t q := by
      rw [abs_mul, abs_mul, abs_of_nonneg (copyResponseEnergy_nonneg beta v true t q),
        abs_of_nonneg (copyResponseEnergy_nonneg beta v false t q)]
    _ ≤ _ := add_le_add
      (mul_le_of_le_one_left (copyResponseEnergy_nonneg beta v true t q) hl)
      (mul_le_of_le_one_left (copyResponseEnergy_nonneg beta v false t q) hr)

theorem copyResponseDriftDifference_integrable
    (hμ : HasFreeIsingLaw (Real.tanh beta) μ) (hb : 0 ≤ beta)
    (v : TreeVertex d) (T : ℝ≥0) :
    Integrable (fun p : ℝ × Joint d => copyResponseDriftDifference beta v p.1.toNNReal p.2)
      ((volume.restrict (Ioc (0 : ℝ) T)).prod (copies beta μ)) := by
  have hm := (stronglyMeasurable_joint_of_isStronglyProgressive
    (copyResponseDriftDifference_progressive beta v)).comp_measurable
      ((measurable_real_toNNReal.comp measurable_fst).prodMk measurable_snd)
  apply ((copyResponseEnergy_integrable hμ hb v true T).add
    (copyResponseEnergy_integrable hμ hb v false T)).mono' hm.aestronglyMeasurable
  exact Eventually.of_forall (fun p => abs_copyResponseDriftDifference_le beta v p.1.toNNReal p.2)

theorem ae_all_abs_driftPrimitive_le_commonResponseCompensator
    (hμ : HasFreeIsingLaw (Real.tanh beta) μ) (hb : 0 ≤ beta)
    (v : TreeVertex d) :
    ∀ᵐ q ∂copies beta μ, ∀ t : ℝ≥0,
      |nnrealTimePrimitive (copyResponseDriftDifference beta v) t q| ≤
        commonResponseCompensator beta v t q := by
  have hiB := ae_intervalIntegrable_horizons_of_joint
    (μ := copies beta μ) (a := copyResponseDriftDifference beta v)
    (fun n => by simpa only [NNReal.coe_natCast] using
      copyResponseDriftDifference_integrable hμ hb v (n : ℝ≥0))
  have hiE := ae_intervalIntegrable_horizons_of_joint
    (μ := copies beta μ)
    (a := fun t q => copyResponseEnergy beta v true t q + copyResponseEnergy beta v false t q)
    (fun n => by
      have hi := (copyResponseEnergy_integrable hμ hb v true (n : ℝ≥0)).add
        (copyResponseEnergy_integrable hμ hb v false (n : ℝ≥0))
      convert hi using 1; rfl)
  filter_upwards [hiB, hiE] with q hB hE
  intro t
  obtain ⟨n, hn⟩ := exists_nat_ge (t : ℝ)
  have hrestrict {f : ℝ → ℝ} (hi : IntervalIntegrable f volume 0 (n : ℝ)) :
      IntervalIntegrable f volume 0 (t : ℝ) :=
    (intervalIntegrable_iff_integrableOn_Ioc_of_le t.coe_nonneg).mpr
      (((intervalIntegrable_iff_integrableOn_Ioc_of_le (Nat.cast_nonneg n)).mp hi).mono_set
        (Ioc_subset_Ioc le_rfl hn))
  unfold nnrealTimePrimitive commonResponseCompensator
  calc
    _ ≤ ∫ s in (0 : ℝ)..(t : ℝ), |copyResponseDriftDifference beta v s.toNNReal q| :=
      intervalIntegral.abs_integral_le_integral_abs t.coe_nonneg
    _ ≤ _ := intervalIntegral.integral_mono t.coe_nonneg (hrestrict (hB n)).abs
      (hrestrict (hE n)) (fun s => abs_copyResponseDriftDifference_le beta v s.toNNReal q)

theorem ae_all_abs_commonResponseCompensator_stopped_le
    (hμ : HasFreeIsingLaw (Real.tanh beta) μ) (hb : 0 ≤ beta)
    (v : TreeVertex d) (n : ℕ) {τ : Joint d → WithTop ℝ≥0}
    (hτ : ∀ q, τ q ≤ commonPosteriorExit beta v n q) :
    ∀ᵐ q ∂copies beta μ, ∀ t : ℝ≥0,
      |stoppedProcess (commonResponseCompensator beta v)
        τ t q| ≤ (n : ℝ) + 1 := by
  filter_upwards [commonResponseCompensator_continuous hμ hb v] with q hc
  intro t
  apply abs_stoppedProcess_le_of_le_exit hc
    (by simp [commonResponseCompensator, nnrealTimePrimitive]; positivity) _ t
  exact (hτ q).trans ((min_le_left _ _).trans (min_le_right _ _))

theorem ae_all_abs_stoppedDriftPrimitive_le
    (hμ : HasFreeIsingLaw (Real.tanh beta) μ) (hb : 0 ≤ beta)
    (v : TreeVertex d) (n : ℕ) {τ : Joint d → WithTop ℝ≥0}
    (hτ : ∀ q, τ q ≤ commonPosteriorExit beta v n q) :
    ∀ᵐ q ∂copies beta μ, ∀ t : ℝ≥0,
      |stoppedProcess (nnrealTimePrimitive (copyResponseDriftDifference beta v))
        τ t q| ≤ (n : ℝ) + 1 := by
  filter_upwards [ae_all_abs_driftPrimitive_le_commonResponseCompensator hμ hb v,
    ae_all_abs_commonResponseCompensator_stopped_le hμ hb v n hτ] with q hB hE
  intro t
  exact (hB _).trans ((le_abs_self _).trans (hE t))

theorem ae_all_abs_cutoffDriftPrimitive_le
    (hμ : HasFreeIsingLaw (Real.tanh beta) μ) (hb : 0 ≤ beta)
    (v : TreeVertex d) (n : ℕ) {τ : Joint d → WithTop ℝ≥0}
    (hτ : ∀ q, τ q ≤ commonPosteriorExit beta v n q) :
    ∀ᵐ q ∂copies beta μ, ∀ t : ℝ≥0,
      |nnrealTimePrimitive
        (StoppedTimePrimitive.stopDensity (copyResponseDriftDifference beta v)
          τ) t q| ≤ (n : ℝ) + 1 := by
  filter_upwards [ae_all_abs_stoppedDriftPrimitive_le hμ hb v n hτ] with q hq
  intro t
  rw [← StoppedTimePrimitive.stoppedProcess_primitive]
  exact hq t

end Problem367.IsingObservationFactor

end

end OAI