openAI-math-dataset / lean /OAI /Geometry /BallPacking /DiskMaps /SmoothConvexSelection.lean
roseking's picture
Add lean source and binary files (part 65)
720fa25 verified
Raw History Blame Contribute Delete
24.9 kB
import Mathlib
import OAI.Geometry.BallPacking.DiskMaps.CubicAreaExhaustion
namespace OAI
noncomputable section
namespace PackingSufficiencySupport.Hamiltonian
section
open scoped ContDiff Topology Manifold
open Set Function
variable {P F : Type*} [NormedAddCommGroup P] [NormedSpace ℝ P] [FiniteDimensional ℝ P]
[NormedAddCommGroup F] [NormedSpace ℝ F]
theorem exists_smooth_convex_selection {Y : Set P} (hY : IsClosed Y)
(S : P → Set F) (hopen : ∀ v, IsOpen {y | v ∈ S y})
(hconv : ∀ y ∈ Y, Convex ℝ (S y)) (hne : ∀ y ∈ Y, (S y).Nonempty) :
∃ c : P → F, ContDiff ℝ ∞ c ∧ ∀ y ∈ Y, c y ∈ S y := by
classical
choose v hv using fun y : Y => hne y y.property
let U : Y → Set P := fun y => {x | v y ∈ S x}
obtain ⟨ρ,hρ⟩ := SmoothPartitionOfUnity.exists_isSubordinate 𝓘(ℝ,P) hY U
(fun y => hopen (v y)) (by
intro y hy
exact mem_iUnion_of_mem ⟨y,hy⟩ (hv ⟨y,hy⟩))
refine ⟨fun y => ∑ᶠ i, ρ i y • v i,?_,?_⟩
· apply contDiff_iff_contDiffAt.mpr
intro y
exact ρ.contDiffAt_finsum (fun _ _ => contDiffAt_const)
· intro y hy
apply ρ.finsum_smul_mem_convex hy _ (hconv y hy)
intro i hi
exact hρ i (subset_tsupport (ρ i) hi)
end
section
open Set Function
theorem exists_strict_interval_extension {a b l u L : ℝ}
(hal : a < l) (hub : u < b) (hLu : u-l < L) (hLb : L < b-a) :
∃ c, a < c ∧ c+L < b ∧ c < l ∧ u < c+L := by
have hh : max a (u-L) < min l (b-L) := by
rw [max_lt_iff,lt_min_iff,lt_min_iff]
constructor <;> constructor <;> linarith
obtain ⟨c,hlo,hhi⟩ := exists_between hh
exact ⟨c,(le_max_left _ _).trans_lt hlo,
by linarith [(lt_of_lt_of_le hhi (min_le_right _ _))],
hhi.trans_le (min_le_left _ _),
by linarith [(lt_of_le_of_lt (le_max_right _ _) hlo)]⟩
theorem exists_strict_nested_intervals {n : ℕ} (a b L : Fin n → ℝ)
(ha : Antitone a) (hb : Monotone b) (hL : StrictMono L)
(hfit : ∀ i, L i < b i-a i) :
∃ c : Fin n → ℝ, (∀ i, a i < c i ∧ c i+L i < b i) ∧
∀ ⦃i j⦄, i < j → c j < c i ∧ c i+L i < c j+L j := by
induction n with
| zero => exact ⟨fun i => i.elim0,by simp,by simp⟩
| succ n ih =>
cases n with
| zero =>
refine ⟨fun i => (a i+b i-L i)/2,?_,?_⟩
· intro i; have := hfit i; constructor <;> linarith
· intro i j hij
have : i = j := by omega
exact (lt_irrefl _ (this ▸ hij)).elim
| succ m =>
obtain ⟨c,hc,hnest⟩ := ih (a ∘ Fin.castSucc) (b ∘ Fin.castSucc)
(L ∘ Fin.castSucc) (ha.comp_monotone Fin.strictMono_castSucc.monotone)
(hb.comp Fin.strictMono_castSucc.monotone) (hL.comp Fin.strictMono_castSucc)
(fun i => hfit i.castSucc)
let i₀ : Fin (m+1) := Fin.last m
let j₀ : Fin (m+2) := Fin.last (m+1)
have hij : i₀.castSucc < j₀ := Fin.castSucc_lt_last _
obtain ⟨d,hd⟩ := exists_strict_interval_extension
((ha hij.le).trans_lt (hc i₀).1)
((hc i₀).2.trans_le (hb hij.le))
(by simpa only [Function.comp_apply,add_sub_cancel_left] using hL hij)
(hfit j₀)
refine ⟨Fin.snoc c d,?_,?_⟩
· intro i
refine Fin.lastCases ?_ (fun j => ?_) i
· simpa only [Fin.snoc_last] using And.intro hd.1 hd.2.1
· simpa only [Fin.snoc_castSucc,Function.comp_apply] using hc j
· intro i j hij'
have hi : i ≠ Fin.last (m+1) := by
intro hh
subst i
exact not_lt_of_ge (Fin.le_last _) hij'
obtain ⟨i,rfl⟩ := Fin.eq_castSucc_of_ne_last hi
revert hij'
refine Fin.lastCases ?_ (fun j hj => ?_) j
· intro _
simp only [Fin.snoc_castSucc,Fin.snoc_last]
rcases lt_or_eq_of_le (Fin.le_last i) with hi | hi
· have hh := hnest hi
exact ⟨hd.2.2.1.trans hh.1,hh.2.trans hd.2.2.2⟩
· subst i
exact hd.2.2
· simpa only [Fin.snoc_castSucc,Function.comp_apply] using
hnest (show i < j from hj)
end
section
open scoped ContDiff Topology
open Set Function
variable {n : ℕ}
def StrictNestedStarts (L c : Fin n → ℝ) : Prop :=
∀ ⦃i j : Fin n⦄, i < j → c j < c i ∧ c i+L i < c j+L j
def IntervalPlacements (L : Fin n → ℝ) (V : Fin n → Set ℝ) : Set (Fin n → ℝ) :=
{c | (∀ i, c i ∈ V i ∧ c i+L i ∈ V i) ∧ StrictNestedStarts L c}
theorem intervalPlacements_convex (L : Fin n → ℝ) (V : Fin n → Set ℝ)
(hV : ∀ i, Convex ℝ (V i)) : Convex ℝ (IntervalPlacements L V) := by
intro c hc d hd α β hα hβ hab
refine ⟨?_,?_⟩
· intro i
have he : (α • c+β • d) i+L i = α*(c i+L i)+β*(d i+L i) := by
simp only [Pi.add_apply,Pi.smul_apply,smul_eq_mul]
have he := congrArg (fun t : ℝ => t*L i) hab
nlinarith only [he]
constructor
· exact hV i (hc.1 i).1 (hd.1 i).1 hα hβ hab
· rw [he]
exact hV i (hc.1 i).2 (hd.1 i).2 hα hβ hab
· intro i j hij
let A : (Fin n → ℝ) →ₗ[ℝ] ℝ := (LinearMap.proj j : (Fin n → ℝ) →ₗ[ℝ] ℝ) - LinearMap.proj i
let B : (Fin n → ℝ) →ₗ[ℝ] ℝ := (LinearMap.proj i : (Fin n → ℝ) →ₗ[ℝ] ℝ) - LinearMap.proj j
have ha : A c < 0 := sub_neg.mpr (hc.2 hij).1
have hb : A d < 0 := sub_neg.mpr (hd.2 hij).1
have ha' : B c < L j-L i := by change c i-c j < _; linarith [(hc.2 hij).2]
have hb' : B d < L j-L i := by change d i-d j < _; linarith [(hd.2 hij).2]
have hh := (convex_halfSpace_lt A.isLinear 0) ha hb hα hβ hab
have hh' := (convex_halfSpace_lt B.isLinear (L j-L i)) ha' hb' hα hβ hab
change (α • c+β • d) j-(α • c+β • d) i < 0 at hh
change (α • c+β • d) i-(α • c+β • d) j < L j-L i at hh'
exact ⟨sub_neg.mp hh,by linarith⟩
variable {P : Type*} [NormedAddCommGroup P] [NormedSpace ℝ P] [FiniteDimensional ℝ P]
theorem exists_smooth_nested_intervals {Y : Set P} (hY : IsClosed Y)
(L : Fin n → ℝ) (hL : StrictMono L) (V : P → Fin n → Set ℝ)
(hopen : ∀ i t, IsOpen {y | t ∈ V y i})
(hconv : ∀ y ∈ Y, ∀ i, Convex ℝ (V y i))
(hroom : ∀ y ∈ Y, ∃ a b : Fin n → ℝ, Antitone a ∧ Monotone b ∧
(∀ i, L i < b i-a i) ∧ ∀ i, Ioo (a i) (b i) ⊆ V y i)
(hpos : ∀ i, 0 < L i) :
∃ c : P → (Fin n → ℝ), ContDiff ℝ ∞ c ∧
∀ y ∈ Y, (∀ i, Icc (c y i) (c y i+L i) ⊆ V y i) ∧
StrictNestedStarts L (c y) := by
have hsopen (c : Fin n → ℝ) : IsOpen {y | c ∈ IntervalPlacements L (V y)} := by
change IsOpen {y | (∀ i, c i ∈ V y i ∧ c i+L i ∈ V y i) ∧ StrictNestedStarts L c}
by_cases hn : StrictNestedStarts L c
· simp only [hn,and_true,ofPred_forall,ofPred_and]
exact isOpen_iInter_of_finite (fun i => (hopen i (c i)).inter (hopen i (c i+L i)))
· simp only [hn,and_false,ofPred_false,isOpen_empty]
have hsne (y : P) (hy : y ∈ Y) : (IntervalPlacements L (V y)).Nonempty := by
obtain ⟨a,b,ha,hb,hfit,hsub⟩ := hroom y hy
obtain ⟨c,hc,hn⟩ := exists_strict_nested_intervals a b L ha hb hL hfit
refine ⟨c,?_,hn⟩
intro i
have hLi := hpos i
exact ⟨hsub i ⟨(hc i).1,by linarith [(hc i).2]⟩,
hsub i ⟨by linarith [(hc i).1],(hc i).2⟩⟩
obtain ⟨c,hc,hmem⟩ := exists_smooth_convex_selection hY
(fun y => IntervalPlacements L (V y)) hsopen
(fun y hy => intervalPlacements_convex L (V y) (hconv y hy)) hsne
refine ⟨c,hc,?_⟩
intro y hy
refine ⟨?_,(hmem y hy).2⟩
intro i
exact (hconv y hy i).ordConnected.out ((hmem y hy).1 i).1 ((hmem y hy).1 i).2
end
section
open scoped ContDiff Topology
open Set Function
variable {P : Type*} [TopologicalSpace P]
def RoundedMargins {n : ℕ} (C : P → Fin n → ℝ) (L w : Fin n → ℝ)
(V : P → Fin n → Set ℝ) (q s : ℝ) (y : P) : Prop :=
0 < s ∧
(∀ i, C y i-s*L i/2 ∈ V y i ∧ C y i+s*L i/2 ∈ V y i) ∧
∀ ⦃i j⦄, i < j →
C y j-q*s*L j/2 < C y i-s*L i/2 ∧
C y i+s*L i/2 < C y j+q*s*L j/2 ∧ w i < q*w j
theorem roundedMargins_open {n : ℕ} (C : P → Fin n → ℝ) (hC : Continuous C)
(L w : Fin n → ℝ) (V : P → Fin n → Set ℝ)
(hV : ∀ i, IsOpen {p : P × ℝ | p.2 ∈ V p.1 i}) :
IsOpen {p : Plane × P | RoundedMargins C L w V p.1.1 p.1.2 p.2} := by
have hlo (i : Fin n) : IsOpen {p : Plane × P | C p.2 i-p.1.2*L i/2 ∈ V p.2 i} :=
(hV i).preimage (continuous_snd.prodMk
(((continuous_apply i).comp (hC.comp continuous_snd)).sub
((continuous_fst.snd.mul continuous_const).div_const 2)))
have hhi (i : Fin n) : IsOpen {p : Plane × P | C p.2 i+p.1.2*L i/2 ∈ V p.2 i} :=
(hV i).preimage (continuous_snd.prodMk
(((continuous_apply i).comp (hC.comp continuous_snd)).add
((continuous_fst.snd.mul continuous_const).div_const 2)))
have hpair (i j : Fin n) : IsOpen {p : Plane × P | i < j →
C p.2 j-p.1.1*p.1.2*L j/2 < C p.2 i-p.1.2*L i/2 ∧
C p.2 i+p.1.2*L i/2 < C p.2 j+p.1.1*p.1.2*L j/2 ∧ w i < p.1.1*w j} := by
by_cases hij : i < j
· simp only [hij,true_implies,ofPred_and]
exact (isOpen_lt (by fun_prop) (by fun_prop)).inter
((isOpen_lt (by fun_prop) (by fun_prop)).inter (isOpen_lt (by fun_prop) (by fun_prop)))
· simp only [hij,false_implies,ofPred_true,isOpen_univ]
change IsOpen {p : Plane × P | 0 < p.1.2 ∧
(∀ i, C p.2 i-p.1.2*L i/2 ∈ V p.2 i ∧ C p.2 i+p.1.2*L i/2 ∈ V p.2 i) ∧
∀ i j, i < j → _}
simp only [ofPred_and,ofPred_forall]
exact (isOpen_lt continuous_const continuous_fst.snd).inter
((isOpen_iInter_of_finite (fun i => (hlo i).inter (hhi i))).inter
(isOpen_iInter_of_finite (fun i => isOpen_iInter_of_finite (fun j => by
simpa only [ofPred_forall,ofPred_and] using hpair i j))))
theorem exists_exact_area_rounded_margins {n : ℕ} {Y : Set P} (hY : IsCompact Y)
(c : P → Fin n → ℝ) (hc : Continuous c) (L w : Fin n → ℝ)
(hw : StrictMono w) (V : P → Fin n → Set ℝ)
(hV : ∀ i, IsOpen {p : P × ℝ | p.2 ∈ V p.1 i})
(hplace : ∀ y ∈ Y, (∀ i, c y i ∈ V y i ∧ c y i+L i ∈ V y i) ∧
StrictNestedStarts L (c y)) :
∃ q k : ℝ, 0 < q ∧ q < 1 ∧ 0 < k ∧
Icc (-q) q ×ˢ Icc (-q) q ⊆ squeezedDisk k ∧ 0 < squeezedArea k ∧
∀ y ∈ Y, RoundedMargins (fun y i => c y i+L i/2) L w V q (4/squeezedArea k) y := by
let C : P → Fin n → ℝ := fun y i => c y i+L i/2
have hC : Continuous C := by
apply continuous_pi
intro i
exact ((continuous_apply i).comp hc).add continuous_const
apply exists_rounded_square_with_control hY continuous_id
(roundedMargins_open C hC L w V hV)
intro y hy
change RoundedMargins C L w V 1 1 y
refine ⟨by norm_num,?_,?_⟩
· intro i
simpa only [C,one_mul,add_sub_cancel_right,add_assoc,add_halves] using (hplace y hy).1 i
· intro i j hij
dsimp [C]
simp only [one_mul,add_sub_cancel_right,add_assoc,add_halves]
exact ⟨((hplace y hy).2 hij).1,((hplace y hy).2 hij).2,hw hij⟩
end
section
open scoped ContDiff Topology BigOperators
open Set Function
theorem exists_thin_rectangle_placement {m : ℕ} (h : Fin m → ℝ)
(hh : ∀ i, 0 < h i) (hmono : StrictMono h) {δ : ℝ} (hδ : 0 < δ) :
∃ (L w c : Fin m → ℝ), (∀ i, 0 < L i) ∧ (∀ i, 0 < w i ∧ w i < 1) ∧
StrictMono w ∧ (∀ i, L i*w i = h i) ∧ StrictNestedStarts L c ∧
∀ i, c i ∈ Ioo 0 (h i+δ/2) ∧ c i+L i ∈ Ioo 0 (h i+δ/2) := by
let B : ℝ := 1+∑ i, h i
have hB : 1 ≤ B := by
have hs : 0 ≤ ∑ i, h i := Finset.sum_nonneg (fun i _ => (hh i).le)
dsimp [B]; linarith
have hiB (i : Fin m) : h i < B := by
have hi := Finset.single_le_sum (s := Finset.univ) (fun j _ => (hh j).le) (Finset.mem_univ i)
dsimp [B]; linarith
let ε := min (δ/8) (1/4)
have hε : 0 < ε := lt_min (by positivity) (by norm_num)
have hεδ : ε ≤ δ/8 := min_le_left _ _
have hε1 : ε ≤ 1/4 := min_le_right _ _
let β := ε/(2*B)
have hd : 0 < 2*B := by linarith
have hβ : 0 < β := div_pos hε hd
have hβ1 : β < 1 := by apply (div_lt_one hd).mpr; linarith
have hB0 : B ≠ 0 := ne_of_gt (by linarith)
have hβB : β*B = ε/2 := by dsimp [β]; field_simp [hB0]
have hsmall (i : Fin m) : β*h i < ε := by
have he := mul_lt_mul_of_pos_left (hiB i) hβ
rw [hβB] at he
linarith
let L i := h i+ε
let w i := h i/(h i+ε)
let c i := ε-β*h i
have hL i : 0 < L i := add_pos (hh i) hε
have hw i : 0 < w i ∧ w i < 1 :=
⟨div_pos (hh i) (hL i),(div_lt_one (hL i)).mpr (by dsimp [L]; linarith)⟩
refine ⟨L,w,c,hL,hw,?_,?_,?_,?_⟩
· intro i j hij
apply (div_lt_div_iff₀ (hL i) (hL j)).mpr
dsimp [L]
have he := mul_lt_mul_of_pos_right (hmono hij) hε
nlinarith
· intro i
dsimp [L,w]
field_simp [show h i+ε ≠ 0 from (hL i).ne']
· intro i j hij
dsimp [c,L]
have he := hmono hij
have he1 := mul_lt_mul_of_pos_left he hβ
have he2 := mul_lt_mul_of_pos_left he (sub_pos.mpr hβ1)
constructor <;> nlinarith
· intro i
have hc : 0 < c i := sub_pos.mpr (hsmall i)
have hcε : c i < ε := by dsimp [c]; nlinarith [mul_pos hβ (hh i)]
have hlower : 0 < c i+L i := add_pos hc (hL i)
have hupper : c i+L i < h i+δ/2 := by dsimp [L]; linarith
exact ⟨⟨hc,(lt_add_of_pos_right (c i) (hL i)).trans hupper⟩,hlower,hupper⟩
end
section
open scoped ContDiff Topology
open Set Function MeasureTheory
def box (c : Plane) (a b : ℝ) : Set Plane :=
Icc (c.1-a) (c.1+a) ×ˢ Icc (c.2-b) (c.2+b)
def openBox (c : Plane) (a b : ℝ) : Set Plane :=
Ioo (c.1-a) (c.1+a) ×ˢ Ioo (c.2-b) (c.2+b)
def roundedMap (k : ℝ) (c : Plane) (a b : ℝ) (x : Plane) : Plane :=
affineRectangle c a b (squareSqueeze k x)
def roundedBox (k : ℝ) (c : Plane) (a b : ℝ) : Set Plane :=
roundedMap k c a b '' closedRoundDisk 1
theorem affineRectangle_injective {a b : ℝ} (ha : a ≠ 0) (hb : b ≠ 0) (c : Plane) :
Injective (affineRectangle c a b) := by
intro x y he
have h1 := congrArg Prod.fst he
have h2 := congrArg Prod.snd he
exact Prod.ext (mul_left_cancel₀ ha (add_left_cancel h1))
(mul_left_cancel₀ hb (add_left_cancel h2))
theorem affineRectangle_smooth (c : Plane) (a b : ℝ) :
ContDiff ℝ ∞ (affineRectangle c a b) :=
contDiff_const.add (diagonalScale a b).contDiff
theorem roundedMap_smooth (k : ℝ) (c : Plane) (a b : ℝ) :
ContDiff ℝ ∞ (roundedMap k c a b) :=
(affineRectangle_smooth c a b).comp (squareSqueeze_smooth k)
theorem roundedMap_injective {k a b : ℝ} (hk : k ≠ 0) (ha : a ≠ 0) (hb : b ≠ 0)
(c : Plane) : Injective (roundedMap k c a b) :=
(affineRectangle_injective ha hb c).comp (squareSqueeze_injective hk)
theorem affineRectangle_fderiv (c : Plane) (a b : ℝ) (x : Plane) :
fderiv ℝ (affineRectangle c a b) x = diagonalScale a b := by
exact ((diagonalScale a b).hasFDerivAt.const_add c).fderiv
theorem roundedMap_det {k a b : ℝ} (c : Plane) (x : Plane) :
(fderiv ℝ (roundedMap k c a b) x).det = a*b*(fderiv ℝ (squareSqueeze k) x).det := by
change (fderiv ℝ (affineRectangle c a b ∘ squareSqueeze k) x).det = _
rw [fderiv_comp x ((affineRectangle_smooth c a b).differentiable (by simp) _)
((squareSqueeze_smooth k).differentiable (by simp) _),affineRectangle_fderiv,
ContinuousLinearMap.det,ContinuousLinearMap.toLinearMap_comp,LinearMap.det_comp]
change (diagonalScale a b).det * _ = _
rw [diagonalScale_det]
theorem roundedMap_det_pos {k a b : ℝ} (hk : 0 < k) (ha : 0 < a) (hb : 0 < b)
(c : Plane) (x : Plane) : 0 < (fderiv ℝ (roundedMap k c a b) x).det := by
rw [roundedMap_det]
exact mul_pos (mul_pos ha hb) (squareSqueeze_det_pos hk x)
theorem roundedMap_mem_openBox {a b : ℝ} (ha : 0 < a) (hb : 0 < b)
(k : ℝ) (c : Plane) (x : Plane) : roundedMap k c a b x ∈ openBox c a b := by
have hx1 := Real.neg_one_lt_tanh (k*x.1)
have hx2 := Real.tanh_lt_one (k*x.1)
have hy1 := Real.neg_one_lt_tanh (k*x.2)
have hy2 := Real.tanh_lt_one (k*x.2)
change (c.1-a < c.1+a*Real.tanh (k*x.1) ∧ c.1+a*Real.tanh (k*x.1) < c.1+a) ∧
(c.2-b < c.2+b*Real.tanh (k*x.2) ∧ c.2+b*Real.tanh (k*x.2) < c.2+b)
constructor <;> constructor <;> nlinarith
theorem box_subset_roundedBox {q k a b : ℝ} (ha : 0 < a) (hb : 0 < b)
(hs : Icc (-q) q ×ˢ Icc (-q) q ⊆ squeezedDisk k) (c : Plane) :
box c (q*a) (q*b) ⊆ roundedBox k c a b := by
intro x hx
let z : Plane := ((x.1-c.1)/a,(x.2-c.2)/b)
have hz : z ∈ Icc (-q) q ×ˢ Icc (-q) q := by
change (-q ≤ (x.1-c.1)/a ∧ (x.1-c.1)/a ≤ q) ∧
(-q ≤ (x.2-c.2)/b ∧ (x.2-c.2)/b ≤ q)
constructor <;> constructor
· apply (le_div_iff₀ ha).mpr; linarith [hx.1.1]
· apply (div_le_iff₀ ha).mpr; linarith [hx.1.2]
· apply (le_div_iff₀ hb).mpr; linarith [hx.2.1]
· apply (div_le_iff₀ hb).mpr; linarith [hx.2.2]
obtain ⟨u,hu,he⟩ := hs hz
refine ⟨u,hu,?_⟩
change affineRectangle c a b (squareSqueeze k u) = x
rw [he]
ext <;> simp [affineRectangle,z,mul_div_cancel₀ _ ha.ne',mul_div_cancel₀ _ hb.ne']
theorem openBox_subset_interior_roundedBox {q k a b : ℝ} (ha : 0 < a) (hb : 0 < b)
(hs : Icc (-q) q ×ˢ Icc (-q) q ⊆ squeezedDisk k) (c : Plane) :
openBox c (q*a) (q*b) ⊆ interior (roundedBox k c a b) := by
apply (isOpen_Ioo.prod isOpen_Ioo).subset_interior_iff.mpr
exact (prod_mono Ioo_subset_Icc_self Ioo_subset_Icc_self).trans
(box_subset_roundedBox ha hb hs c)
theorem roundedBox_compact (k : ℝ) (c : Plane) (a b : ℝ) :
IsCompact (roundedBox k c a b) :=
(closedRoundDisk_isCompact 1).image (roundedMap_smooth k c a b).continuous
theorem roundedBox_volume {a b : ℝ} (ha : 0 ≤ a) (hb : 0 ≤ b)
(k : ℝ) (c : Plane) :
(volume (roundedBox k c a b)).toReal = a*b*squeezedArea k := by
change (volume ((affineRectangle c a b ∘ squareSqueeze k) '' closedRoundDisk 1)).toReal = _
rw [image_comp]
exact affineRectangle_squeezedArea ha hb c k
end
section
open scoped ContDiff Topology
open Set Function Filter
variable {E F : Type*} [NormedAddCommGroup E] [NormedSpace ℝ E]
[NormedAddCommGroup F] [NormedSpace ℝ F]
variable [FiniteDimensional ℝ E]
theorem isInvertible_of_det_ne_zero {A : E →L[ℝ] E} (hA : A.det ≠ 0) : A.IsInvertible :=
⟨(A.toLinearMap.equivOfDetNeZero hA).toContinuousLinearEquiv,rfl⟩
theorem smooth_map_nhds_eq {f : E → E} {x : E} (hf : ContDiffAt ℝ ∞ f x)
(hd : (fderiv ℝ f x).det ≠ 0) : map f (𝓝 x) = 𝓝 (f x) := by
obtain ⟨e,he⟩ := isInvertible_of_det_ne_zero hd
have hs := hf.hasStrictFDerivAt (by simp)
rw [← he] at hs
exact hs.map_nhds_eq_of_equiv
theorem image_interior_subset_of_det_ne_zero {f : E → E} {S : Set E}
(hf : ∀ x ∈ interior S, ContDiffAt ℝ ∞ f x)
(hd : ∀ x ∈ interior S, (fderiv ℝ f x).det ≠ 0) :
f '' interior S ⊆ interior (f '' S) := by
rintro _ ⟨x,hx,rfl⟩
apply mem_interior_iff_mem_nhds.mpr
have hh := Filter.image_mem_map (m := f) (mem_interior_iff_mem_nhds.mp hx)
rwa [smooth_map_nhds_eq (hf x hx) (hd x hx)] at hh
variable [FiniteDimensional ℝ F]
omit [FiniteDimensional ℝ E] [FiniteDimensional ℝ F] in
theorem det_fderiv_conjugate (e : E ≃L[ℝ] F) {f : F → F} {x : E}
(hf : DifferentiableAt ℝ f (e x)) :
(fderiv ℝ (fun x => e.symm (f (e x))) x).det = (fderiv ℝ f (e x)).det := by
have hd := e.symm.hasFDerivAt.comp x (hf.hasFDerivAt.comp x e.hasFDerivAt)
change (fderiv ℝ (e.symm ∘ f ∘ e) x).det = _
rw [hd.fderiv]
change LinearMap.det (e.symm.toLinearEquiv.toLinearMap ∘ₗ
(fderiv ℝ f (e x)).toLinearMap ∘ₗ e.toLinearEquiv.toLinearMap) = _
exact LinearMap.det_conj _ e.symm.toLinearEquiv
end
open scoped ContDiff Topology
open Set Function MeasureTheory
def FitsPolar (c : Plane) (a b : ℝ) : Prop :=
0 < c.1-a ∧ c.1+a < 1 ∧ 0 < c.2-b ∧ c.2+b < 1
theorem openBox_subset_polar {c : Plane} {a b : ℝ} (hfit : FitsPolar c a b) :
openBox c a b ⊆ areaPolarDomain := by
intro x hx
exact ⟨hfit.1.trans hx.1.1,hfit.2.2.1.trans hx.2.1,hx.2.2.trans hfit.2.2.2⟩
def polarRoundedMap (k : ℝ) (c : Plane) (a b : ℝ) (x : Plane) : Plane :=
areaPolar (roundedMap k c a b x)
def polarRoundedDisk (k : ℝ) (c : Plane) (a b : ℝ) : Set Plane :=
polarRoundedMap k c a b '' closedRoundDisk 1
theorem polarRoundedMap_injective {k a b : ℝ} (hk : 0 < k) (ha : 0 < a) (hb : 0 < b)
(c : Plane) (hfit : FitsPolar c a b) : Injective (polarRoundedMap k c a b) := by
intro x y he
apply roundedMap_injective hk.ne' ha.ne' hb.ne' c
exact areaPolar_injOn (openBox_subset_polar hfit (roundedMap_mem_openBox ha hb k c x))
(openBox_subset_polar hfit (roundedMap_mem_openBox ha hb k c y)) he
theorem polarRoundedMap_smooth {a b : ℝ} (ha : 0 < a) (hb : 0 < b)
(k : ℝ) (c : Plane) (hfit : FitsPolar c a b) : ContDiff ℝ ∞ (polarRoundedMap k c a b) := by
apply contDiff_iff_contDiffAt.mpr
intro x
exact (areaPolar_smoothAt (openBox_subset_polar hfit (roundedMap_mem_openBox ha hb k c x)).1).comp x
(roundedMap_smooth k c a b).contDiffAt
theorem polarRoundedMap_det {a b : ℝ} (ha : 0 < a) (hb : 0 < b)
(k : ℝ) (c : Plane) (hfit : FitsPolar c a b) (x : Plane) :
(fderiv ℝ (polarRoundedMap k c a b) x).det = (fderiv ℝ (roundedMap k c a b) x).det := by
have hp := (openBox_subset_polar hfit (roundedMap_mem_openBox ha hb k c x)).1
change (fderiv ℝ (areaPolar ∘ roundedMap k c a b) x).det = _
rw [fderiv_comp x ((areaPolar_smoothAt hp).differentiableAt (by simp))
((roundedMap_smooth k c a b).differentiable (by simp) _),
ContinuousLinearMap.det,ContinuousLinearMap.toLinearMap_comp,LinearMap.det_comp]
change (fderiv ℝ areaPolar (roundedMap k c a b x)).det * _ = _
rw [areaPolar_det hp,one_mul]
theorem polarRoundedMap_det_pos {k a b : ℝ} (hk : 0 < k) (ha : 0 < a) (hb : 0 < b)
(c : Plane) (hfit : FitsPolar c a b) (x : Plane) :
0 < (fderiv ℝ (polarRoundedMap k c a b) x).det := by
rw [polarRoundedMap_det ha hb k c hfit]
exact roundedMap_det_pos hk ha hb c x
theorem polarRoundedMap_capacity {a b : ℝ} (ha : 0 < a) (hb : 0 < b)
(k : ℝ) (c : Plane) (hfit : FitsPolar c a b) (x : Plane) :
Real.pi * radiusSq (polarRoundedMap k c a b x) = (roundedMap k c a b x).1 :=
areaPolar_capacity (openBox_subset_polar hfit (roundedMap_mem_openBox ha hb k c x)).1.le
theorem polarRoundedDisk_volume {a b : ℝ} (ha : 0 < a) (hb : 0 < b)
(k : ℝ) (c : Plane) (hfit : FitsPolar c a b) :
(volume (polarRoundedDisk k c a b)).toReal = a*b*squeezedArea k := by
change (volume ((areaPolar ∘ roundedMap k c a b) '' closedRoundDisk 1)).toReal = _
rw [image_comp]
change (volume (areaPolar '' roundedBox k c a b)).toReal = _
rw [areaPolar_image_volume (roundedBox_compact k c a b).measurableSet (by
rintro z ⟨x,_,rfl⟩
exact openBox_subset_polar hfit (roundedMap_mem_openBox ha hb k c x))]
exact roundedBox_volume ha.le hb.le k c
theorem polarRoundedDisk_nested {k a b a' b' : ℝ} {c c' : Plane}
(ha' : 0 < a') (hb' : 0 < b') (hfit' : FitsPolar c' a' b')
(hnest : roundedBox k c a b ⊆ interior (roundedBox k c' a' b')) :
polarRoundedDisk k c a b ⊆ interior (polarRoundedDisk k c' a' b') := by
change (areaPolar ∘ roundedMap k c a b) '' closedRoundDisk 1 ⊆
interior ((areaPolar ∘ roundedMap k c' a' b') '' closedRoundDisk 1)
rw [image_comp,image_comp]
apply (image_mono hnest).trans
apply image_interior_subset_of_det_ne_zero
· intro x hx
obtain ⟨z,_,rfl⟩ := interior_subset hx
exact areaPolar_smoothAt (openBox_subset_polar hfit' (roundedMap_mem_openBox ha' hb' k c' z)).1
· intro x hx
obtain ⟨z,_,rfl⟩ := interior_subset hx
rw [areaPolar_det (openBox_subset_polar hfit' (roundedMap_mem_openBox ha' hb' k c' z)).1]
norm_num
variable {P : Type*} [NormedAddCommGroup P] [NormedSpace ℝ P]
theorem polarRoundedFamily_smoothOn {A : Set P} (_hA : IsOpen A)
(C : P → Plane) (hC : ContDiff ℝ ∞ C) {a b : ℝ} (ha : 0 < a) (hb : 0 < b)
(k : ℝ) (hfit : ∀ y ∈ A, FitsPolar (C y) a b) :
ContDiffOn ℝ ∞ (fun p : P × Plane => polarRoundedMap k (C p.1) a b p.2) (A ×ˢ univ) := by
intro p hp
apply ContDiffAt.contDiffWithinAt
have hg : ContDiff ℝ ∞ (fun p : P × Plane => roundedMap k (C p.1) a b p.2) :=
(hC.comp contDiff_fst).add
((diagonalScale a b).contDiff.comp ((squareSqueeze_smooth k).comp contDiff_snd))
exact (areaPolar_smoothAt
(openBox_subset_polar (hfit p.1 hp.1) (roundedMap_mem_openBox ha hb k (C p.1) p.2)).1).comp p hg.contDiffAt
end PackingSufficiencySupport.Hamiltonian
end
end OAI