File size: 7,771 Bytes
59d1c80
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
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
142
143
144
145
146
147
148
149
150
151
152
import OAI.Geometry.IsometricImmersion.Pulses.PulseProfiles
import OAI.Geometry.IsometricImmersion.Flows.FlowImageFirstBounds
import OAI.Geometry.IsometricImmersion.Caps.FixedMetricLowerCap

namespace OAI

noncomputable section
open Set Filter Function
open scoped ContDiff Topology BigOperators

namespace SmoothLocal.Pulse
open SmoothLocal.Geometry SmoothLocal.Flow SmoothLocal.ODE SmoothLocal.Weighted

theorem scalar_fderiv_coordinate_bound {q : Coord → ℝ} {p v : Coord} {M : ℝ}
    (_hM : 0 ≤ M) (hpartial : ∀ i : Fin 2, |coordPartial i q p| ≤ M) :
    |fderiv ℝ q p v| ≤ M*(|v 0|+|v 1|) := by
  have he : v = (v 0) • Pi.single 0 (1 : ℝ) + (v 1) • Pi.single 1 (1 : ℝ) := by
    ext i
    fin_cases i <;> simp
  conv_lhs => rw [he, map_add, map_smul, map_smul]
  change |v 0 * coordPartial 0 q p + v 1 * coordPartial 1 q p| ≤ _
  calc
    _ ≤ |v 0 * coordPartial 0 q p| + |v 1 * coordPartial 1 q p| := abs_add_le _ _
    _ = |v 0| * |coordPartial 0 q p|+|v 1| * |coordPartial 1 q p| := by rw [abs_mul,abs_mul]
    _ ≤ |v 0| * M+|v 1| * M := add_le_add
      (mul_le_mul_of_nonneg_left (hpartial 0) (abs_nonneg _))
      (mul_le_mul_of_nonneg_left (hpartial 1) (abs_nonneg _))
    _ = _ := by ring

theorem quotient_change_from_origin
    {q : Coord → ℝ} {U : Set Coord} {M : ℝ}
    (hq : ContDiffOn ℝ ∞ q U) (hU : IsOpen U) (hSU : modelSquare ⊆ U) (hM : 0 ≤ M)
    (hpartial : ∀ p ∈ modelSquare, ∀ i : Fin 2, |coordPartial i q p| ≤ M)
    {p : Coord} (hp : p ∈ modelSquare) : |q p-q 0| ≤ M*(|p 0|+|p 1|) := by
  have hz : (0 : Coord) ∈ modelSquare := by constructor <;> intro i <;> norm_num
  have hconv : Convex ℝ modelSquare := convex_Icc _ _
  have hseg (t : ℝ) (ht : t ∈ Icc (0 : ℝ) 1) : t • p ∈ modelSquare := by
    have h := hconv hp hz ht.1 (sub_nonneg.mpr ht.2) (by ring)
    simpa only [smul_zero, add_zero] using h
  have hder (t : ℝ) (ht : t ∈ Icc (0 : ℝ) 1) :
      HasDerivAt (fun s : ℝ => q (s • p)) (fderiv ℝ q (t • p) p) t := by
    have hdq := ((hq.contDiffAt (hU.mem_nhds (hSU (hseg t ht)))).differentiableAt (by simp)).hasFDerivAt
    have hdp : HasDerivAt (fun s : ℝ => s • p) p t := by
      have ht := (hasDerivAt_id t).smul_const p
      change HasDerivAt (fun s : ℝ => s • p) ((1 : ℝ) • p) t at ht
      rw [one_smul] at ht
      exact ht
    exact hdq.comp_hasDerivAt t hdp
  have hb (t : ℝ) (ht : t ∈ Icc (0 : ℝ) 1) :
      ‖deriv (fun s : ℝ => q (s • p)) t‖ ≤ M*(|p 0|+|p 1|) := by
    rw [(hder t ht).deriv, Real.norm_eq_abs]
    exact scalar_fderiv_coordinate_bound hM (hpartial (t • p) (hseg t ht))
  have h := (convex_Icc (0 : ℝ) 1).norm_image_sub_le_of_norm_deriv_le
    (fun t ht => (hder t ht).differentiableAt) hb
    (by simp : (0 : ℝ) ∈ Icc (0 : ℝ) 1) (by simp : (1 : ℝ) ∈ Icc (0 : ℝ) 1)
  simpa only [zero_smul, one_smul, sub_zero, norm_one, mul_one, Real.norm_eq_abs] using h

variable {q : Coord → ℝ} {U : Set Coord} {Y : ℝ → ℝ → ℝ}
variable (hq : ContDiffOn ℝ ∞ q U) (hU : IsOpen U) (hSU : modelSquare ⊆ U)
variable (hY : ContinuousOn (uncurry Y) (Icc (-2 : ℝ) 2 ×ˢ Icc (-2 : ℝ) 2))
variable (hrange : ∀ s ∈ Icc (-2 : ℝ) 2, ∀ t ∈ Icc (-2 : ℝ) 2, Y s t ∈ Icc (-3 : ℝ) 3)
variable (hstart : ∀ s ∈ Icc (-2 : ℝ) 2, Y s 0 = s)
variable (hode : ∀ s ∈ Icc (-2 : ℝ) 2, ∀ t ∈ Icc (-2 : ℝ) 2,
  HasDerivWithinAt (Y s) (-q (coordinatePoint t (Y s t))) (Icc (-2 : ℝ) 2) t)
include hq hU hSU hY hrange hstart hode

theorem flow_segment_coordinate_sum
    (hsmall : ∀ p ∈ modelSquare, |q p| ≤ (1 : ℝ)/100)
    {q0 T r s t u : ℝ} (hq0 : |q0| ≤ 1/20) (_hT : 0 < T) (hT2 : T < 2)
    (hs : s ∈ Ioo (-2 : ℝ) 2) (ht : t ∈ Icc (-T) T) (hu : u ∈ Icc (-T) T)
    (htheta : |Y s t+q0*t| ≤ r) :
    |u|+|Y s u| ≤ r+107*T/100 := by
  have ht' : t ∈ Ioo (-2 : ℝ) 2 := ⟨by linarith [ht.1],by linarith [ht.2]⟩
  have hu' : u ∈ Ioo (-2 : ℝ) 2 := ⟨by linarith [hu.1],by linarith [hu.2]⟩
  have habst : |t| ≤ T := abs_le.mpr ht
  have habsu : |u| ≤ T := abs_le.mpr hu
  have hdt : |u-t| ≤ 2*T := (abs_sub u t).trans (by linarith)
  have hmove := (cap_flow_time_lipschitz hq hU hSU hY hrange hstart hode hsmall hs ht' hu').trans
    (mul_le_mul_of_nonneg_left hdt (by norm_num : (0 : ℝ) ≤ 1/100))
  have hprod : |q0*t| ≤ (1/20)*T := by
    rw [abs_mul]
    exact mul_le_mul hq0 habst (abs_nonneg _) (by norm_num)
  have hyt : |Y s t| ≤ r+(1/20)*T := by
    calc
      |Y s t| = |(Y s t+q0*t)-q0*t| := by congr 1; ring
      _ ≤ |Y s t+q0*t|+|q0*t| := abs_sub _ _
      _ ≤ _ := add_le_add htheta hprod
  have hyu : |Y s u| ≤ |Y s u-Y s t|+|Y s t| := by
    calc
      |Y s u| = |(Y s u-Y s t)+Y s t| := by congr 1; ring
      _ ≤ _ := abs_add_le _ _
  linarith

theorem flow_segment_quotient_near_center
    (hsmall : ∀ p ∈ modelSquare, |q p| ≤ (1 : ℝ)/100)
    {M q0 L T r s t : ℝ} (hM : 0 ≤ M) (hL : 0 < L)
    (hpartial : ∀ p ∈ modelSquare, ∀ i : Fin 2, |coordPartial i q p| ≤ M)
    (hq0 : |q0| ≤ 1/20) (hcenter : |q 0-q0| ≤ 1/(100*L))
    (hT : 0 < T) (hT2 : T < 2) (hs : s ∈ Ioo (-2 : ℝ) 2) (ht : t ∈ Icc (-T) T)
    (htheta : |Y s t+q0*t| ≤ r)
    (hrsmall : M*(r+107*T/100) ≤ 9/(100*L)) :
    ∀ u ∈ Icc (-T) T, |q (coordinatePoint u (Y s u))-q0| ≤ 1/(10*L) := by
  intro u hu
  have hu2 : u ∈ Icc (-2 : ℝ) 2 := ⟨by linarith [hu.1],by linarith [hu.2]⟩
  have hp : coordinatePoint u (Y s u) ∈ modelSquare := coordinatePoint_mem_modelSquare
    ⟨by linarith [hu2.1],by linarith [hu2.2]⟩
    (hrange s ⟨hs.1.le,hs.2.le⟩ u hu2)
  have hnorm := flow_segment_coordinate_sum hq hU hSU hY hrange hstart hode
    hsmall hq0 hT hT2 hs ht hu htheta
  have hlocal : |q (coordinatePoint u (Y s u))-q 0| ≤ M*(|u|+|Y s u|) := by
    simpa [coordinatePoint] using quotient_change_from_origin hq hU hSU hM hpartial hp
  have hsum : |q (coordinatePoint u (Y s u))-q0| ≤
      |q (coordinatePoint u (Y s u))-q 0|+|q 0-q0| := by
    calc
      _ = |(q (coordinatePoint u (Y s u))-q 0)+(q 0-q0)| := by congr 1; ring
      _ ≤ _ := abs_add_le _ _
  have ha := hsum.trans (add_le_add (hlocal.trans
    (mul_le_mul_of_nonneg_left hnorm hM)) hcenter)
  have heq : 9/(100*L)+1/(100*L) = 1/(10*L) := by field_simp [hL.ne']; ring
  exact ha.trans ((add_le_add hrsmall le_rfl).trans_eq heq)

theorem actual_shear_seed_distance
    {q0 epsilon T s t : ℝ} (hT : 0 < T) (hT2 : T < 2)
    (hs : s ∈ Ioo (-2 : ℝ) 2) (ht : t ∈ Icc (-T) T)
    (hclose : ∀ u ∈ Icc (-T) T, |q (coordinatePoint u (Y s u))-q0| ≤ epsilon) :
    |Y s t+q0*t-s| ≤ epsilon*|t| := by
  have hd (u : ℝ) (hu : u ∈ Icc (-T) T) :
      HasDerivAt (fun a => Y s a+q0*a) (-q (coordinatePoint u (Y s u))+q0) u := by
    have hu2 : u ∈ Ioo (-2 : ℝ) 2 := ⟨by linarith [hu.1],by linarith [hu.2]⟩
    have hh := (cap_flow_time_hasDerivAt hq hU hSU hY hrange hstart hode hs hu2).add
      ((hasDerivAt_id u).const_mul q0)
    change HasDerivAt (fun a : ℝ => Y s a + q0 * a)
      (-q (coordinatePoint u (Y s u)) + q0 * 1) u at hh
    rw [mul_one] at hh
    exact hh
  have hb (u : ℝ) (hu : u ∈ Icc (-T) T) :
      ‖deriv (fun a => Y s a+q0*a) u‖ ≤ epsilon := by
    rw [(hd u hu).deriv, Real.norm_eq_abs]
    have heq : -q (coordinatePoint u (Y s u))+q0 = -(q (coordinatePoint u (Y s u))-q0) := by ring
    rw [heq,abs_neg]
    exact hclose u hu
  have h := (convex_Icc (-T) T).norm_image_sub_le_of_norm_deriv_le
    (fun u hu => (hd u hu).differentiableAt) hb
    (show (0 : ℝ) ∈ Icc (-T) T by constructor <;> linarith) ht
  simpa only [hstart s ⟨hs.1.le,hs.2.le⟩, mul_zero, add_zero, sub_zero, Real.norm_eq_abs] using h

end SmoothLocal.Pulse

end

end OAI