import Mathlib import OAI.Geometry.BallPacking.Necessity.FreezeJ import OAI.Geometry.BallPacking.Necessity.SchauderBounds namespace OAI noncomputable section open scoped ContDiff Topology open Set Function Filter open scoped ContDiff Topology Manifold open Set Function Filter MeasureTheory open Set Function MeasureTheory open Set Function open SymplecticBallPacking.Hamiltonian (Plane planarCurl) open SymplecticBallPacking.Hamiltonian (Plane planarCurl angularOneForm radiusSq planarArea planarArea_apply) open SymplecticBallPacking.Hamiltonian (Plane planarCurl angularOneForm) open SymplecticBallPacking.Hamiltonian (Plane angularOneForm) open SymplecticBallPacking.Hamiltonian open SymplecticBallPacking.Hamiltonian (Plane) open Set Filter Function open Set Filter MeasureTheory open scoped Topology open Set Filter Finset open scoped ContDiff Topology Classical open Set Filter open scoped BoundedContinuousFunction ContDiff Topology open Set Function Filter Topology open scoped NNReal open scoped ContDiff Topology BoundedContinuousFunction open Function open scoped ContDiff Topology open Set Filter Function namespace HigherDimensionalBallPacking.Rigidity theorem exists_nested_complex_cutoffs : ∃ (χ θ : ℂ → ℝ) (D : ℝ), 0 ≤ D ∧ ContDiff ℝ ∞ χ ∧ HasCompactSupport χ ∧ ContDiff ℝ ∞ θ ∧ HasCompactSupport θ ∧ tsupport χ ⊆ Metric.closedBall (0:ℂ) 2 ∧ tsupport θ ⊆ Metric.closedBall (0:ℂ) 3 ∧ χ =ᶠ[𝓝 0] (fun _ => (1:ℝ)) ∧ (∀ z ∈ tsupport χ, θ z=1) ∧ (∀ z, |χ z| ≤ 1 ∧ |θ z| ≤ 1) ∧ (∀ z, ‖fderiv ℝ χ z‖ ≤ D ∧ ‖fderiv ℝ (fderiv ℝ χ) z‖ ≤ D ∧ ‖fderiv ℝ θ z‖ ≤ D) := by let χ : ContDiffBump (0:ℂ) := ⟨1,2,by norm_num,by norm_num⟩ let θ : ContDiffBump (0:ℂ) := ⟨2,3,by norm_num,by norm_num⟩ have hχ : ContDiff ℝ ∞ (χ : ℂ → ℝ) := χ.contDiff have hθ : ContDiff ℝ ∞ (θ : ℂ → ℝ) := θ.contDiff have hχD : ContDiff ℝ ∞ (fderiv ℝ (χ : ℂ → ℝ)) := hχ.fderiv_right (by simp) obtain ⟨D₁,hD₁,hB₁⟩ := ((χ.hasCompactSupport.fderiv ℝ).isCompact_range (hχ.continuous_fderiv (by simp))).isBounded.exists_pos_norm_le have hbD2 : Bornology.IsBounded (range (fderiv ℝ (fderiv ℝ (χ : ℂ → ℝ)))) := (((χ.hasCompactSupport.fderiv ℝ).fderiv ℝ).isCompact_range (hχD.continuous_fderiv (by simp))).isBounded obtain ⟨D₂,hD₂,hB₂⟩ := hbD2.exists_pos_norm_le obtain ⟨D₃,hD₃,hB₃⟩ := ((θ.hasCompactSupport.fderiv ℝ).isCompact_range (hθ.continuous_fderiv (by simp))).isBounded.exists_pos_norm_le refine ⟨χ,θ,D₁+D₂+D₃,by positivity,hχ,χ.hasCompactSupport,hθ,θ.hasCompactSupport,?_,?_,?_,?_,?_,?_⟩ · rw [χ.tsupport_eq] · rw [θ.tsupport_eq] · exact χ.eventuallyEq_one · intro z hz rw [χ.tsupport_eq] at hz exact θ.one_of_mem_closedBall hz · intro z constructor · rw [abs_of_nonneg χ.nonneg] exact χ.le_one · rw [abs_of_nonneg θ.nonneg] exact θ.le_one · intro z have h1 := hB₁ _ (mem_range_self z) have h2 := hB₂ _ (mem_range_self z) have h3 := hB₃ _ (mem_range_self z) exact ⟨by linarith,by linarith,by linarith⟩ open scoped Topology ContDiff open Set Filter Function section variable {E F : Type*} [NormedAddCommGroup E] [NormedSpace ℝ E] [NormedAddCommGroup F] [NormedSpace ℝ F] theorem derivative_bound_of_holder_and_values (f : E → F) (hf : Differentiable ℝ f) {M C r α : ℝ} (hM : 0 ≤ M) (hC : 0 ≤ C) (hr : 0 < r) (hα : 0 ≤ α) (hv : ∀ z ∈ Metric.closedBall (0:E) r, ‖f z‖ ≤ M) (hD : ∀ z ∈ Metric.closedBall (0:E) r, ‖fderiv ℝ f z-fderiv ℝ f 0‖ ≤ C*‖z‖^α) : ‖fderiv ℝ f 0‖ ≤ 2*M/r+C*r^α := by apply ContinuousLinearMap.opNorm_le_of_unit_norm (by positivity) intro v hvn have hrv : r • v ∈ Metric.closedBall (0:E) r := by simp [Metric.mem_closedBall,dist_zero_right,norm_smul,Real.norm_eq_abs,abs_of_pos hr,hvn] have h0 : (0:E) ∈ Metric.closedBall (0:E) r := Metric.mem_closedBall_self hr.le have herr := (convex_closedBall (0:E) r).norm_image_sub_le_of_norm_fderiv_le' (fun z _ => hf z) (φ := fderiv ℝ f 0) (C := C*r^α) (fun z hz => (hD z hz).trans (mul_le_mul_of_nonneg_left (Real.rpow_le_rpow (norm_nonneg _) (by simpa using hz) hα) hC)) h0 hrv simp only [sub_zero,norm_smul,Real.norm_eq_abs,abs_of_pos hr,hvn,mul_one] at herr have hval : ‖f (r • v)-f 0‖ ≤ 2*M := (norm_sub_le _ _).trans (by linarith [hv (r • v) hrv,hv 0 h0]) have hsum := norm_sub_le (f (r • v)-f 0) (f (r • v)-f 0-(fderiv ℝ f 0) (r • v)) rw [sub_sub_cancel] at hsum rw [map_smul,norm_smul,Real.norm_eq_abs,abs_of_pos hr] at hsum rw [map_smul] at herr have hbound : r*‖(fderiv ℝ f 0) v‖ ≤ 2*M+(C*r^α)*r := by linarith have hh : ‖(fderiv ℝ f 0) v‖ ≤ (2*M+(C*r^α)*r)/r := (le_div_iff₀ hr).mpr (by nlinarith) convert hh using 1 field_simp theorem norm_fderiv_tendsto_zero_of_holder {f : ℕ → E → F} (hf : ∀ j, Differentiable ℝ (f j)) {C α : ℝ} (hC : 0 ≤ C) (hα : 0 < α) (hD : ∀ᶠ j in atTop, ∀ x y, ‖fderiv ℝ (f j) x-fderiv ℝ (f j) y‖ ≤ C*‖x-y‖^α) (hv : TendstoUniformlyOn f (fun _ => (0:F)) atTop (Metric.closedBall (0:E) 1)) : Tendsto (fun j => ‖fderiv ℝ (f j) 0‖) atTop (𝓝 0) := by apply tendsto_order.2 constructor · intro a ha exact Eventually.of_forall (fun j => ha.trans_le (norm_nonneg _)) intro ε hε have hpow : Tendsto (fun r : ℝ => C*r^α) (𝓝[>] 0) (𝓝 0) := by simpa [Real.zero_rpow (ne_of_gt hα)] using ((tendsto_const_nhds : Tendsto (fun _ : ℝ => C) (𝓝[>] 0) (𝓝 C)).mul ((Real.continuousAt_rpow_const 0 α (Or.inr hα.le)).tendsto.mono_left nhdsWithin_le_nhds)) have hs := hpow.eventually (gt_mem_nhds (show 0 < ε/2 by linarith)) have hs' : ∀ᶠ r : ℝ in 𝓝[>] 0, r < 1 := (eventually_lt_nhds (show (0:ℝ) < 1 by norm_num)).filter_mono nhdsWithin_le_nhds have hpos : ∀ᶠ r : ℝ in 𝓝[>] 0, 0 < r := self_mem_nhdsWithin obtain ⟨r,hr,hr1,hsmall⟩ := (hpos.and (hs'.and hs)).exists have hδ : 0 < ε*r/8 := by positivity have hev := (Metric.tendstoUniformlyOn_iff.mp hv) (ε*r/8) hδ filter_upwards [hev,hD] with j hj hjD have hb := derivative_bound_of_holder_and_values (f j) (hf j) (M := ε*r/8) (C := C) hδ.le hC hr hα.le (fun z hz => le_of_lt (by have hh := hj z (Metric.closedBall_subset_closedBall hr1.le hz) simpa [dist_eq_norm] using hh)) (fun z _ => by simpa using hjD z 0) have hid : 2*(ε*r/8)/r=ε/4 := by field_simp; ring rw [hid] at hb linarith end open scoped ContDiff Topology BoundedContinuousFunction open Set Filter Function section variable {E : Type} [NormedAddCommGroup E] [NormedSpace ℂ E] [CompleteSpace E] local instance gradientLimitsC1NormedAddCommGroup (α : ℝ) : NormedAddCommGroup (C1HolderSpace E α) := inferInstance local instance gradientLimitsC1NormedSpace (α : ℝ) : NormedSpace ℝ (C1HolderSpace E α) := inferInstance local instance gradientLimitsCompactNormedAddCommGroup (F : Type) [NormedAddCommGroup F] [NormedSpace ℝ F] (R : ℝ) : NormedAddCommGroup (CompactHolderSpace F R) := inferInstance local instance gradientLimitsCompactNormedSpace (F : Type) [NormedAddCommGroup F] [NormedSpace ℝ F] (R : ℝ) : NormedSpace ℝ (CompactHolderSpace F R) := inferInstance private theorem exists_small_principal_const (B K : ℝ) : ∃ δ : ℝ, 0 < δ ∧ δ ≤ 1 ∧ B*max δ ((2*δ)^((2:ℝ)/3)*K^((1:ℝ)/3)) ≤ 1/2 := by let g : ℝ → ℝ := fun r => B*max r ((2*r)^((2:ℝ)/3)*K^((1:ℝ)/3)) have hg : Continuous g := by exact continuous_const.mul (continuous_id.max (((Real.continuous_rpow_const (by norm_num : (0:ℝ) ≤ 2/3)).comp (continuous_const.mul continuous_id)).mul continuous_const)) have hg0 : g 0=0 := by simp [g,Real.zero_rpow (show (2:ℝ)/3 ≠ 0 by norm_num)] have hev : ∀ᶠ r : ℝ in 𝓝[>] 0, g r < 1/2 := by have ht : Tendsto g (𝓝[>] 0) (𝓝 (g 0)) := hg.continuousAt.tendsto.mono_left nhdsWithin_le_nhds exact ht.eventually (gt_mem_nhds (show g 0 < (1:ℝ)/2 by rw [hg0]; norm_num)) have hr1 : ∀ᶠ r : ℝ in 𝓝[>] 0, r < 1 := (eventually_lt_nhds (show (0:ℝ) < 1 by norm_num)).filter_mono nhdsWithin_le_nhds have hr0 : ∀ᶠ r : ℝ in 𝓝[>] 0, 0 < r := self_mem_nhdsWithin obtain ⟨r,h0,h1,hg⟩ := (hr0.and (hr1.and hev)).exists exact ⟨r,h0,h1.le,hg.le⟩ theorem smallCR_sequence_derivative_zero (u : ℕ → ℂ → E) (hu : ∀ j, ContDiff ℝ ∞ (u j)) (A : ℕ → ℂ → E →L[ℝ] E) (hA : ∀ j, ContDiff ℝ ∞ (A j)) {L K : ℝ} (hL : 0 ≤ L) (hK : 0 ≤ K) (huD : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (u j) z‖ ≤ L) (hAD : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (A j) z‖ ≤ K) (hCR : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, fderiv ℝ (u j) z Complex.I-Complex.I • fderiv ℝ (u j) z 1= A j z (fderiv ℝ (u j) z 1)) (hu0 : TendstoUniformlyOn u (fun _ => (0:E)) atTop (Metric.closedBall (0:ℂ) 3)) (hA0 : TendstoUniformlyOn A (fun _ => (0:E →L[ℝ] E)) atTop (Metric.closedBall (0:ℂ) 3)) : Tendsto (fun j => ‖fderiv ℝ (u j) 0‖) atTop (𝓝 0) := by obtain ⟨χ,θ,D,hD,hχ,hχc,hθ,hθc,hχ2,hθ3,hχ1,hθ1,hχθ,hd⟩ := exists_nested_complex_cutoffs have hχ3 : tsupport χ ⊆ Metric.closedBall (0:ℂ) 3 := hχ2.trans (Metric.closedBall_subset_closedBall (by norm_num)) let B := 2*‖compactCRInverse (E := E) 3‖*‖c1HolderDx (E := E)‖ obtain ⟨δ,hδ,hδ1,hsmall⟩ := exists_small_principal_const B (K+D) have hu1 : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖u j z‖ ≤ 1 := by filter_upwards [Metric.tendstoUniformlyOn_iff.mp hu0 1 (by norm_num)] with j hj intro z hz exact le_of_lt (by simpa [dist_eq_norm] using hj z hz) have hAδ : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖A j z‖ ≤ δ := by filter_upwards [Metric.tendstoUniformlyOn_iff.mp hA0 δ hδ] with j hj intro z hz exact le_of_lt (by simpa [dist_eq_norm] using hj z hz) let v : ℕ → ℂ → E := fun j z => χ z • u j z have hv : ∀ j, ContDiff ℝ ∞ (v j) := fun j => hχ.smul (hu j) have hv0 : TendstoUniformlyOn v (fun _ => (0:E)) atTop (Metric.closedBall (0:ℂ) 1) := by rw [Metric.tendstoUniformlyOn_iff] intro ε hε filter_upwards [Metric.tendstoUniformlyOn_iff.mp hu0 ε hε] with j hj intro z hz simp only [dist_zero_left,v,norm_smul,Real.norm_eq_abs] exact (mul_le_mul_of_nonneg_right (hχθ z).1 (norm_nonneg _)).trans_lt (by simpa only [one_mul,dist_zero_left] using hj z (Metric.closedBall_subset_closedBall (by norm_num : (1:ℝ) ≤ 3) hz)) have hvD : ∀ᶠ j in atTop, ∀ x y, ‖fderiv ℝ (v j) x-fderiv ℝ (v j) y‖ ≤ localSchauderBound E 3 D L (K+D)*‖x-y‖^((1:ℝ)/3) := by filter_upwards [huD,hAD,hCR,hu1,hAδ] with j hjD hjAD hjCR hj1 hjAδ let AA : ℂ → E →L[ℝ] E := fun z => θ z • A j z have hAA : ContDiff ℝ ∞ AA := hθ.smul (hA j) have hAAc : HasCompactSupport AA := hθc.smul_right have hAAs : tsupport AA ⊆ Metric.closedBall (0:ℂ) 3 := (tsupport_smul_subset_left θ (A j)).trans hθ3 have hb := cutoff_smul_bounds hθ (hA j) hθ3 (C := 1) (D := D) (M := δ) (L := K) (by norm_num) hD hδ.le hK (fun z => (hχθ z).2) (fun z => (hd z).2.2) hjAδ hjAD have hAAv : ∀ z, ‖AA z‖ ≤ δ := by simpa only [one_mul] using hb.1 have hAAD : ∀ z, ‖fderiv ℝ AA z‖ ≤ K+D := by intro z exact (hb.2 z).trans (by nlinarith) apply cutoff_smallCR_schauder 3 χ hχ hχc hχ3 AA hAA hAAc hAAs (u j) (hu j) hD hL (add_nonneg hK hD) hδ.le hδ1 (fun z => (hd z).1) (fun z => (hd z).2.1) (fun z hz => hj1 z (hχ3 hz)) (fun z hz => hjD z (hχ3 hz)) hAAv hAAD · intro z hz rw [show AA z=A j z by simp only [AA,hθ1 z hz,one_smul]] exact hjCR z (hχ3 hz) · dsimp [B] at hsmall nlinarith only [hsmall] have hC : 0 ≤ localSchauderBound E 3 D L (K+D) := by dsimp [localSchauderBound] positivity have hlim := norm_fderiv_tendsto_zero_of_holder (fun j => (hv j).differentiable (by simp)) hC (by norm_num : (0:ℝ) < 1/3) hvD hv0 convert hlim using 1 funext j congr 1 apply Filter.EventuallyEq.fderiv_eq filter_upwards [hχ1] with z hz simp only [v,hz,one_smul] end open scoped Topology open Set Filter Function section variable {E F G : Type*} [NormedAddCommGroup E] [NormedSpace ℝ E] [NormedAddCommGroup F] [NormedSpace ℝ F] [NormedAddCommGroup G] [NormedSpace ℝ G] omit [NormedSpace ℝ E] [NormedSpace ℝ F] [NormedAddCommGroup G] [NormedSpace ℝ G] in theorem locally_uniform_comp_uniform_constant [NormedSpace ℝ E] [NormedSpace ℝ F] [NormedAddCommGroup G] [NormedSpace ℝ G] {f : ℕ → E → F} {v : E → F} (hv : TendstoLocallyUniformly f v atTop) {x : E} (hvc : ContinuousAt v x) {g : ℕ → G → E} {K : Set G} (hg : TendstoUniformlyOn g (fun _ => x) atTop K) : TendstoUniformlyOn (fun j z => f j (g j z)) (fun _ => v x) atTop K := by rw [Metric.tendstoUniformlyOn_iff] intro ε hε have he := show {p : F × F | dist p.1 p.2 < ε/2} ∈ uniformity F from Metric.dist_mem_uniformity (by linarith) obtain ⟨U,hU,hUf⟩ := hv _ he x obtain ⟨V,hV,hVc⟩ := Metric.continuousAt_iff.mp hvc (ε/2) (by linarith) obtain ⟨δ,hδ,hδU⟩ := Metric.mem_nhds_iff.mp hU have hmin : 0 < min δ V := lt_min hδ hV filter_upwards [hUf,Metric.tendstoUniformlyOn_iff.mp hg (min δ V) hmin] with j hj hjg intro z hz have hgdist : dist (g j z) x < min δ V := by simpa [dist_comm] using hjg z hz have hmem : g j z ∈ U := hδU (hgdist.trans_le (min_le_left _ _)) have h1 := hj (g j z) hmem have h2 := hVc (lt_of_lt_of_le hgdist (min_le_right _ _)) have ht := dist_triangle (v x) (v (g j z)) (f j (g j z)) rw [dist_comm (v x) (v (g j z))] at ht linarith omit [NormedSpace ℝ E] [NormedSpace ℝ F] [NormedAddCommGroup G] [NormedSpace ℝ G] in theorem continuousAt_comp_uniform_constant [NormedSpace ℝ E] [NormedSpace ℝ F] [NormedAddCommGroup G] [NormedSpace ℝ G] {g : E → F} {x : E} (hg : ContinuousAt g x) {u : ℕ → G → E} {K : Set G} (hu : TendstoUniformlyOn u (fun _ => x) atTop K) : TendstoUniformlyOn (fun j z => g (u j z)) (fun _ => g x) atTop K := by rw [Metric.tendstoUniformlyOn_iff] intro ε hε obtain ⟨δ,hδ,hb⟩ := Metric.continuousAt_iff.mp hg ε hε filter_upwards [Metric.tendstoUniformlyOn_iff.mp hu δ hδ] with j hj intro z hz rw [dist_comm] exact hb (by simpa [dist_comm] using hj z hz) omit [NormedSpace ℝ E] [NormedSpace ℝ F] [NormedAddCommGroup G] [NormedSpace ℝ G] in theorem uniform_constant_prod [NormedSpace ℝ E] [NormedSpace ℝ F] [NormedAddCommGroup G] [NormedSpace ℝ G] {x : ℕ → E} {p : E} (hx : Tendsto x atTop (𝓝 p)) {u : ℕ → G → F} {q : F} {K : Set G} (hu : TendstoUniformlyOn u (fun _ => q) atTop K) : TendstoUniformlyOn (fun j z => (x j,u j z)) (fun _ => (p,q)) atTop K := by rw [Metric.tendstoUniformlyOn_iff] intro ε hε filter_upwards [Metric.tendsto_nhds.mp hx ε hε,Metric.tendstoUniformlyOn_iff.mp hu ε hε] with j hj hju intro z hz rw [Prod.dist_eq] exact max_lt (by simpa [dist_comm] using hj) (hju z hz) theorem affine_rescale_uniform_constant {x : ℕ → E} {c : E} (hx : Tendsto x atTop (𝓝 c)) {r : ℕ → ℝ} (hr : Tendsto r atTop (𝓝 0)) {K : Set E} (hK : Bornology.IsBounded K) : TendstoUniformlyOn (fun j z => x j+r j • z) (fun _ => c) atTop K := by obtain ⟨M,hM,hMb⟩ := hK.exists_pos_norm_le rw [Metric.tendstoUniformlyOn_iff] intro ε hε have hsmall : ∀ᶠ j in atTop, dist (x j) c+|r j| * M < ε := by have ht : Tendsto (fun j => dist (x j) c+|r j| * M) atTop (𝓝 0) := by simpa using (hx.dist (tendsto_const_nhds (x := c))).add (hr.abs.mul_const M) exact ht.eventually (gt_mem_nhds hε) filter_upwards [hsmall] with j hj intro z hz rw [dist_comm,dist_eq_norm] have he : x j+r j • z-c=(x j-c)+r j • z := by abel rw [he] apply (norm_add_le _ _).trans_lt rw [norm_smul,Real.norm_eq_abs] apply lt_of_le_of_lt _ hj rw [dist_eq_norm] exact add_le_add le_rfl (mul_le_mul_of_nonneg_left (hMb z hz) (abs_nonneg _)) theorem rescaled_maps_uniform_constant {f : ℕ → E → F} {v : E → F} (hv : TendstoLocallyUniformly f v atTop) {x : ℕ → E} {c : E} (hvc : ContinuousAt v c) (hx : Tendsto x atTop (𝓝 c)) {r : ℕ → ℝ} (hr : Tendsto r atTop (𝓝 0)) {K : Set E} (hK : Bornology.IsBounded K) : TendstoUniformlyOn (fun j z => f j (x j+r j • z)) (fun _ => v c) atTop K := locally_uniform_comp_uniform_constant hv hvc (affine_rescale_uniform_constant hx hr hK) end open scoped ContDiff Topology open Set Filter Function section open HigherDimensionalBallPacking.Rigidity def frameConjugation {n : ℕ} (S : Phase n ≃L[ℝ] Phase n) : End n →L[ℝ] End n := (ContinuousLinearMap.compL ℝ (Phase n) (Phase n) (Phase n) S.toContinuousLinearMap).comp ((ContinuousLinearMap.compL ℝ (Phase n) (Phase n) (Phase n)).flip S.symm.toContinuousLinearMap) @[simp] theorem frameConjugation_apply {n : ℕ} (S : Phase n ≃L[ℝ] Phase n) (B : End n) : frameConjugation S B=S.toContinuousLinearMap.comp (B.comp S.symm.toContinuousLinearMap) := rfl theorem frozenCoefficient_fderiv {n : ℕ} (S : Phase n ≃L[ℝ] Phase n) (J : End n) {B : ℂ → End n} (hB : Differentiable ℝ B) (z : ℂ) : fderiv ℝ (frozenCoefficient S J B) z=(frameConjugation S).comp (fderiv ℝ B z) := ((frameConjugation S).hasFDerivAt.comp z ((hB z).hasFDerivAt.sub_const J)).fderiv theorem frozen_CR_no_gradient_loss {n : ℕ} (u : ℕ → ℂ → Phase n) (hu : ∀ j, ContDiff ℝ ∞ (u j)) (B : ℕ → ℂ → End n) (hB : ∀ j, ContDiff ℝ ∞ (B j)) (p : Phase n) (J : End n) (hJ : Compatible J) {L K : ℝ} (hL : 0 ≤ L) (hK : 0 ≤ K) (huD : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (u j) z‖ ≤ L) (hBD : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (B j) z‖ ≤ K) (hCR : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, fderiv ℝ (u j) z Complex.I=B j z (fderiv ℝ (u j) z 1)) (hu0 : TendstoUniformlyOn u (fun _ => p) atTop (Metric.closedBall (0:ℂ) 3)) (hB0 : TendstoUniformlyOn B (fun _ => J) atTop (Metric.closedBall (0:ℂ) 3)) : Tendsto (fun j => ‖fderiv ℝ (u j) 0‖) atTop (𝓝 0) := by obtain ⟨S,hS⟩ := compatible_standard_frame hJ let U : ℕ → ℂ → Phase n := fun j => centeredFrame S p (u j) let A : ℕ → ℂ → End n := fun j => frozenCoefficient S J (B j) have hU : ∀ j, ContDiff ℝ ∞ (U j) := fun j => centeredFrame_smooth S p (hu j) have hA : ∀ j, ContDiff ℝ ∞ (A j) := fun j => frozenCoefficient_smooth S J (hB j) have hUD : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (U j) z‖ ≤ ‖S.toContinuousLinearMap‖*L := by filter_upwards [huD] with j hj intro z hz rw [show fderiv ℝ (U j) z=S.toContinuousLinearMap.comp (fderiv ℝ (u j) z) from centeredFrame_fderiv S p ((hu j).differentiable (by simp)) z] exact (S.toContinuousLinearMap.opNorm_comp_le _).trans (mul_le_mul_of_nonneg_left (hj z hz) (norm_nonneg _)) have hAD : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (A j) z‖ ≤ ‖frameConjugation S‖*K := by filter_upwards [hBD] with j hj intro z hz rw [show fderiv ℝ (A j) z=(frameConjugation S).comp (fderiv ℝ (B j) z) from frozenCoefficient_fderiv S J ((hB j).differentiable (by simp)) z] exact ((frameConjugation S).opNorm_comp_le _).trans (mul_le_mul_of_nonneg_left (hj z hz) (norm_nonneg _)) have hACR : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, fderiv ℝ (U j) z Complex.I-Complex.I • fderiv ℝ (U j) z 1= A j z (fderiv ℝ (U j) z 1) := by filter_upwards [hCR] with j hj intro z hz exact frozen_CR_equation S J hS p ((hu j).differentiable (by simp)) (B j) (hj z hz) have hU0 : TendstoUniformlyOn U (fun _ => (0:Phase n)) atTop (Metric.closedBall (0:ℂ) 3) := by have hc : ContinuousAt (fun x : Phase n => S (x-p)) p := S.continuous.continuousAt.comp (continuousAt_id.sub continuousAt_const) convert continuousAt_comp_uniform_constant hc hu0 using 1 all_goals try simp only [U,sub_self,map_zero] all_goals rfl have hA0 : TendstoUniformlyOn A (fun _ => (0:End n)) atTop (Metric.closedBall (0:ℂ) 3) := by have hc : ContinuousAt (fun x : End n => frameConjugation S (x-J)) J := (frameConjugation S).continuous.continuousAt.comp (continuousAt_id.sub continuousAt_const) convert continuousAt_comp_uniform_constant hc hB0 using 1 all_goals try simp only [A,frameConjugation_apply,sub_self,map_zero] all_goals rfl have hlim := smallCR_sequence_derivative_zero U hU A hA (mul_nonneg (norm_nonneg S.toContinuousLinearMap) hL) (mul_nonneg (norm_nonneg (frameConjugation S)) hK) hUD hAD hACR hU0 hA0 apply squeeze_zero (fun j => norm_nonneg _) (fun j => show ‖fderiv ℝ (u j) 0‖ ≤ ‖S.symm.toContinuousLinearMap‖*‖fderiv ℝ (U j) 0‖ from ?_) (by simpa using hlim.const_mul ‖S.symm.toContinuousLinearMap‖) have he : fderiv ℝ (u j) 0=S.symm.toContinuousLinearMap.comp (fderiv ℝ (U j) 0) := by rw [show fderiv ℝ (U j) 0=S.toContinuousLinearMap.comp (fderiv ℝ (u j) 0) from centeredFrame_fderiv S p ((hu j).differentiable (by simp)) 0] apply ContinuousLinearMap.ext intro z change (fderiv ℝ (u j) 0) z=S.symm (S ((fderiv ℝ (u j) 0) z)) simp rw [he] exact S.symm.toContinuousLinearMap.opNorm_comp_le _ end open scoped ContDiff Topology open Set Filter Function section open HigherDimensionalBallPacking.Rigidity theorem lineHomotopy_contDiffAt {n : ℕ} {J : Phase n → End n} (hJs : ContDiff ℝ ∞ J) (hJ : ∀ x, Compatible (J x)) {y : ℝ × Phase n} (hy : y.1 ∈ Icc (0:ℝ) 1) : ContDiffAt ℝ ∞ (fun y : ℝ × Phase n => lineHomotopy J y.1 y.2) y := contDiffAt_interpolateJ (hJs.contDiffAt.comp y contDiffAt_snd) contDiffAt_fst (hJ y.2) hy theorem homotopy_CR_no_gradient_loss {n : ℕ} {J : Phase n → End n} (hJs : ContDiff ℝ ∞ J) (hJ : ∀ x, Compatible (J x)) (t : ℕ → ℝ) (ht : ∀ j, t j ∈ Icc (0:ℝ) 1) {s : ℝ} (hts : Tendsto t atTop (𝓝 s)) (u : ℕ → ℂ → Phase n) (hu : ∀ j, ContDiff ℝ ∞ (u j)) (p : Phase n) {L : ℝ} (hL : 0 ≤ L) (huD : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (u j) z‖ ≤ L) (hCR : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, fderiv ℝ (u j) z Complex.I=lineHomotopy J (t j) (u j z) (fderiv ℝ (u j) z 1)) (hu0 : TendstoUniformlyOn u (fun _ => p) atTop (Metric.closedBall (0:ℂ) 3)) : Tendsto (fun j => ‖fderiv ℝ (u j) 0‖) atTop (𝓝 0) := by let H : ℝ × Phase n → End n := fun y => lineHomotopy J y.1 y.2 let B : ℕ → ℂ → End n := fun j z => H (t j,u j z) have hs : s ∈ Icc (0:ℝ) 1 := isClosed_Icc.mem_of_tendsto hts (Eventually.of_forall ht) have hH (y : ℝ × Phase n) (hy : y.1 ∈ Icc (0:ℝ) 1) : ContDiffAt ℝ ∞ H y := lineHomotopy_contDiffAt hJs hJ hy have hB (j : ℕ) : ContDiff ℝ ∞ (B j) := by rw [contDiff_iff_contDiffAt] intro z exact ContDiffAt.comp (g := H) (f := fun z => (t j,u j z)) z (hH (t j,u j z) (ht j)) (contDiffAt_const.prodMk (hu j).contDiffAt) have hBounded : Bornology.IsBounded ((fderiv ℝ H) '' (Icc (0:ℝ) 1 ×ˢ Metric.closedBall p 1)) := ((isCompact_Icc.prod (isCompact_closedBall p 1)).image_of_continuousOn (fun y hy => ((hH y hy.1).continuousAt_fderiv (by simp)).continuousWithinAt)).isBounded obtain ⟨K,hK,hKb⟩ := hBounded.exists_pos_norm_le have hB0 : TendstoUniformlyOn B (fun _ => H (s,p)) atTop (Metric.closedBall (0:ℂ) 3) := by convert continuousAt_comp_uniform_constant (hH (s,p) hs).continuousAt (uniform_constant_prod hts hu0) using 1 have hBD : ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (B j) z‖ ≤ K*L := by filter_upwards [huD,Metric.tendstoUniformlyOn_iff.mp hu0 1 (by norm_num)] with j hj hju intro z hz have hmem : (t j,u j z) ∈ Icc (0:ℝ) 1 ×ˢ Metric.closedBall p 1 := ⟨ht j,by simpa [Metric.mem_closedBall,dist_comm] using (hju z hz).le⟩ have hd : HasFDerivAt (fun z => (t j,u j z)) ((0 : ℂ →L[ℝ] ℝ).prod (fderiv ℝ (u j) z)) z := (hasFDerivAt_const (t j) z).prodMk ((hu j).differentiable (by simp) z).hasFDerivAt have he : fderiv ℝ (B j) z=(fderiv ℝ H (t j,u j z)).comp ((0 : ℂ →L[ℝ] ℝ).prod (fderiv ℝ (u j) z)) := (HasFDerivAt.comp (g := H) (f := fun z => (t j,u j z)) z ((hH (t j,u j z) (ht j)).differentiableAt (by simp)).hasFDerivAt hd).fderiv rw [he] apply ((fderiv ℝ H (t j,u j z)).opNorm_comp_le _).trans have hnorm : ‖(0 : ℂ →L[ℝ] ℝ).prod (fderiv ℝ (u j) z)‖=‖fderiv ℝ (u j) z‖ := by rw [ContinuousLinearMap.opNorm_prod,Prod.norm_def,norm_zero,max_eq_right (norm_nonneg _)] rw [hnorm] exact mul_le_mul (hKb _ ⟨(t j,u j z),hmem,rfl⟩) (hj z hz) (norm_nonneg _) hK.le exact frozen_CR_no_gradient_loss u hu B hB p (H (s,p)) (lineHomotopy_compatible hJ hs p) hL (mul_nonneg hK.le hL) huD hBD hCR hu0 hB0 end open scoped ContDiff Topology open Set Filter Function section variable {F : Type*} [NormedAddCommGroup F] [NormedSpace ℝ F] def rescaleMap (u : ℂ → F) (x : ℂ) (r : ℝ) : ℂ → F := fun z => u (x+r • z) theorem rescaleMap_smooth {u : ℂ → F} (hu : ContDiff ℝ ∞ u) (x : ℂ) (r : ℝ) : ContDiff ℝ ∞ (rescaleMap u x r) := by exact ContDiff.comp (g := u) (f := fun z : ℂ => x+r • z) hu (contDiff_const.add (contDiff_id.const_smul r)) theorem rescaleMap_fderiv {u : ℂ → F} (hu : Differentiable ℝ u) (x : ℂ) (r : ℝ) (z : ℂ) : fderiv ℝ (rescaleMap u x r) z=r • fderiv ℝ u (x+r • z) := by have hd : HasFDerivAt (fun z : ℂ => x+r • z) (r • ContinuousLinearMap.id ℝ ℂ) z := by have hh := (hasFDerivAt_const (𝕜 := ℝ) x z).add ((hasFDerivAt_id (𝕜 := ℝ) z).const_smul r) simp only [zero_add] at hh convert hh using 1 rfl have he := (HasFDerivAt.comp (g := u) (f := fun z : ℂ => x+r • z) z (hu (x+r • z)).hasFDerivAt hd).fderiv simp only [Function.comp_def,ContinuousLinearMap.comp_smul, ContinuousLinearMap.comp_id] at he convert he using 1 rfl theorem rescaleMap_norm_fderiv {u : ℂ → F} (hu : Differentiable ℝ u) (x : ℂ) (r : ℝ) (z : ℂ) : ‖fderiv ℝ (rescaleMap u x r) z‖=|r| * ‖fderiv ℝ u (x+r • z)‖ := by rw [rescaleMap_fderiv hu,norm_smul,Real.norm_eq_abs] theorem weighted_rescale_bounds {u : ℂ → F} (hu : Differentiable ℝ u) {x c : ℂ} {R : ℝ} (hg : 0 < ‖fderiv ℝ u x‖) (hm : 6 ≤ (R-dist x c)*‖fderiv ℝ u x‖) (hb : ∀ y ∈ Metric.closedBall x ((R-dist x c)/2), ‖fderiv ℝ u y‖ ≤ 2*‖fderiv ℝ u x‖) : ‖fderiv ℝ (rescaleMap u x ‖fderiv ℝ u x‖⁻¹) 0‖=1 ∧ ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (rescaleMap u x ‖fderiv ℝ u x‖⁻¹) z‖ ≤ 2 := by have hr : 0 ≤ ‖fderiv ℝ u x‖⁻¹ := inv_nonneg.mpr hg.le constructor · rw [rescaleMap_norm_fderiv hu,abs_of_nonneg hr,smul_zero,add_zero,inv_mul_cancel₀ hg.ne'] · intro z hz have hhalf : ‖fderiv ℝ u x‖⁻¹*3 ≤ (R-dist x c)/2 := by have hh := mul_le_mul_of_nonneg_right hm hr rw [mul_assoc,mul_inv_cancel₀ hg.ne',mul_one] at hh linarith have hmem : x+‖fderiv ℝ u x‖⁻¹ • z ∈ Metric.closedBall x ((R-dist x c)/2) := by rw [Metric.mem_closedBall,dist_eq_norm,add_sub_cancel_left,norm_smul,Real.norm_eq_abs, abs_of_nonneg hr] exact (mul_le_mul_of_nonneg_left (by simpa using hz : ‖z‖ ≤ 3) hr).trans hhalf rw [rescaleMap_norm_fderiv hu,abs_of_nonneg hr] calc _ ≤ ‖fderiv ℝ u x‖⁻¹*(2*‖fderiv ℝ u x‖) := mul_le_mul_of_nonneg_left (hb _ hmem) hr _ = 2 := by rw [mul_left_comm,inv_mul_cancel₀ hg.ne',mul_one] theorem rescaleMap_CR {n : ℕ} {J : Phase n → End n} {u : ℂ → Phase n} (hu : Differentiable ℝ u) (hCR : ∀ z, PseudoHolomorphicAt J u z) (x : ℂ) (r : ℝ) (z : ℂ) : fderiv ℝ (rescaleMap u x r) z Complex.I= J (rescaleMap u x r z) (fderiv ℝ (rescaleMap u x r) z 1) := by rw [rescaleMap_fderiv hu] simpa only [smul_apply,map_smul,mul_one,rescaleMap] using congrArg (fun v : Phase n => r • v) ((hCR (x+r • z)).2 1) end open scoped ContDiff Topology open Set Filter Function section variable {F : Type*} [NormedAddCommGroup F] [NormedSpace ℝ F] theorem weighted_gradient_maximum (f : ℂ → F) (hf : ContDiff ℝ ∞ f) (c : ℂ) {R : ℝ} (hR : 0 < R) (hgrad : 0 < ‖fderiv ℝ f c‖) : ∃ x ∈ Metric.ball c R, R*‖fderiv ℝ f c‖ ≤ (R-dist x c)*‖fderiv ℝ f x‖ ∧ ‖fderiv ℝ f c‖ ≤ ‖fderiv ℝ f x‖ ∧ ∀ y ∈ Metric.closedBall x ((R-dist x c)/2), ‖fderiv ℝ f y‖ ≤ 2*‖fderiv ℝ f x‖ := by let g : ℂ → ℝ := fun z => (R-dist z c)*‖fderiv ℝ f z‖ have hg : Continuous g := (continuous_const.sub (continuous_id.dist continuous_const)).mul ((hf.continuous_fderiv (by simp)).norm) obtain ⟨x,hx,hxm⟩ := (isCompact_closedBall c R).exists_isMaxOn (Metric.nonempty_closedBall.mpr hR.le) hg.continuousOn have hcm : c ∈ Metric.closedBall c R := Metric.mem_closedBall_self hR.le have hcx : R*‖fderiv ℝ f c‖ ≤ (R-dist x c)*‖fderiv ℝ f x‖ := by simpa only [Set.mem_ofPred_eq,g,dist_self,sub_zero] using hxm hcm have hxp : 0 < R-dist x c := by have hm : 0 < (R-dist x c)*‖fderiv ℝ f x‖ := (mul_pos hR hgrad).trans_le hcx exact pos_of_mul_pos_left hm (norm_nonneg _) have hxmem : x ∈ Metric.ball c R := by rw [Metric.mem_ball] linarith have hgx : ‖fderiv ℝ f c‖ ≤ ‖fderiv ℝ f x‖ := by apply le_of_mul_le_mul_left (a := R) · calc R*‖fderiv ℝ f c‖ ≤ (R-dist x c)*‖fderiv ℝ f x‖ := hcx _ ≤ R*‖fderiv ℝ f x‖ := mul_le_mul_of_nonneg_right (by linarith [dist_nonneg (x := x) (y := c)]) (norm_nonneg _) · exact hR refine ⟨x,hxmem,hcx,hgx,?_⟩ intro y hy have hyx : dist y x ≤ (R-dist x c)/2 := Metric.mem_closedBall.mp hy have hyc : dist y c ≤ (R+dist x c)/2 := by have hh := dist_triangle y x c linarith have hymem : y ∈ Metric.closedBall c R := by rw [Metric.mem_closedBall] linarith have hxy := hxm hymem change (R-dist y c)*‖fderiv ℝ f y‖ ≤ (R-dist x c)*‖fderiv ℝ f x‖ at hxy have hb : ((R-dist x c)/2)*‖fderiv ℝ f y‖ ≤ (R-dist y c)*‖fderiv ℝ f y‖ := mul_le_mul_of_nonneg_right (by linarith) (norm_nonneg _) have hh := hb.trans hxy nlinarith end open scoped ContDiff Topology open Set Filter Function open HigherDimensionalBallPacking.Rigidity theorem locally_uniform_reindex {E F : Type*} [TopologicalSpace E] [UniformSpace F] {u : ℕ → E → F} {v : E → F} (hv : TendstoLocallyUniformly u v atTop) {a : ℕ → ℕ} (ha : Tendsto a atTop atTop) : TendstoLocallyUniformly (fun j => u (a j)) v atTop := by intro V hV x obtain ⟨U,hU,hUV⟩ := hv V hV x exact ⟨U,hU,ha.eventually hUV⟩ theorem homotopy_C0_gradient_bound {n : ℕ} {J : Phase n → End n} (hJs : ContDiff ℝ ∞ J) (hJ : ∀ x, Compatible (J x)) (t : ℕ → ℝ) (ht : ∀ j, t j ∈ Icc (0:ℝ) 1) {s : ℝ} (hts : Tendsto t atTop (𝓝 s)) (u : ℕ → ℂ → Phase n) (hu : ∀ j, ContDiff ℝ ∞ (u j)) (hCR : ∀ j z, PseudoHolomorphicAt (lineHomotopy J (t j)) (u j) z) (v : ℂ → Phase n) (hv : TendstoLocallyUniformly u v atTop) (c : ℂ) {R : ℝ} (_hR : 0 ≤ R) : ∃ L ≥ 0, ∀ᶠ j in atTop, ∀ z ∈ Metric.closedBall c R, ‖fderiv ℝ (u j) z‖ ≤ L := by by_contra hn have hbad (j : ℕ) : ∃ i ≥ j, ∃ z ∈ Metric.closedBall c R, (j:ℝ)+1 < ‖fderiv ℝ (u i) z‖ := by have hnot : ¬ ∀ᶠ i in atTop, ∀ z ∈ Metric.closedBall c R, ‖fderiv ℝ (u i) z‖ ≤ (j:ℝ)+1 := by intro hh exact hn ⟨(j:ℝ)+1,by positivity,hh⟩ rw [Filter.eventually_atTop] at hnot push Not at hnot obtain ⟨i,hi,z,hz,hbig⟩ := hnot j exact ⟨i,hi,z,hz,hbig⟩ choose a ha z hz hbig using hbad have hat : Tendsto a atTop atTop := tendsto_atTop_mono ha tendsto_id have hpos (j : ℕ) : 0 < ‖fderiv ℝ (u (a j)) (z j)‖ := lt_trans (by positivity) (hbig j) choose x hx hweight hlarger hlocal using (fun j => weighted_gradient_maximum (u (a j)) (hu (a j)) (z j) (by norm_num : (0:ℝ)<1) (hpos j)) have hxmem (j : ℕ) : x j ∈ Metric.closedBall c (R+1) := by have h1 : dist (x j) (z j) < 1 := hx j have h2 : dist (z j) c ≤ R := hz j rw [Metric.mem_closedBall] linarith [dist_triangle (x j) (z j) c] obtain ⟨d,hd,φ,hφ,hφx⟩ := (isCompact_closedBall c (R+1)).tendsto_subseq hxmem let b : ℕ → ℕ := fun j => a (φ j) have hbt : Tendsto b atTop atTop := hat.comp hφ.tendsto_atTop let g : ℕ → ℝ := fun j => ‖fderiv ℝ (u (b j)) (x (φ j))‖ have hgp (j : ℕ) : 0 < g j := (hpos (φ j)).trans_le (hlarger (φ j)) have hgb (j : ℕ) : (φ j:ℝ)+1 < g j := (hbig (φ j)).trans_le (hlarger (φ j)) have hgt : Tendsto g atTop atTop := by apply tendsto_atTop_mono (fun j => (le_add_of_nonneg_right (by norm_num : (0:ℝ) ≤ 1)).trans (hgb j).le) exact tendsto_natCast_atTop_atTop.comp hφ.tendsto_atTop let r : ℕ → ℝ := fun j => (g j)⁻¹ have hrt : Tendsto r atTop (𝓝 0) := tendsto_inv_atTop_zero.comp hgt let U : ℕ → ℂ → Phase n := fun j => rescaleMap (u (b j)) (x (φ j)) (r j) have hUs (j : ℕ) : ContDiff ℝ ∞ (U j) := rescaleMap_smooth (hu (b j)) _ _ have hlim : TendstoUniformlyOn U (fun _ => v d) atTop (Metric.closedBall (0:ℂ) 3) := by have hv' := locally_uniform_reindex hv hbt have hvc : Continuous v := hv.continuous (Eventually.of_forall (fun j => (hu j).continuous)).frequently convert rescaled_maps_uniform_constant hv' hvc.continuousAt hφx hrt (Metric.isBounded_closedBall (x := (0:ℂ)) (r := 3)) using 1 rfl have hUb : ∀ᶠ j in atTop, ‖fderiv ℝ (U j) 0‖=1 ∧ ∀ z ∈ Metric.closedBall (0:ℂ) 3, ‖fderiv ℝ (U j) z‖ ≤ 2 := by filter_upwards [eventually_ge_atTop (6:ℕ)] with j hj apply weighted_rescale_bounds ((hu (b j)).differentiable (by simp)) (hgp j) · have hφj : j ≤ φ j := hφ.id_le j have h6 : (6:ℝ) ≤ φ j := by exact_mod_cast le_trans hj hφj have hw := hweight (φ j) dsimp [g,b] at hgb nlinarith [hbig (φ j)] · exact hlocal (φ j) have hUCR : ∀ j z, fderiv ℝ (U j) z Complex.I= lineHomotopy J (t (b j)) (U j z) (fderiv ℝ (U j) z 1) := by intro j z exact rescaleMap_CR ((hu (b j)).differentiable (by simp)) (hCR (b j)) _ _ _ have hzero := homotopy_CR_no_gradient_loss hJs hJ (fun j => t (b j)) (fun j => ht (b j)) (hts.comp hbt) U hUs (v d) (by norm_num : (0:ℝ) ≤ 2) (hUb.mono (fun j hj => hj.2)) (Eventually.of_forall (fun j z _ => hUCR j z)) hlim have hone : Tendsto (fun j => ‖fderiv ℝ (U j) 0‖) atTop (𝓝 1) := tendsto_const_nhds.congr' (hUb.mono (fun j hj => hj.1.symm)) have he : (0:ℝ)=1 := tendsto_nhds_unique hzero hone norm_num at he end HigherDimensionalBallPacking.Rigidity end end OAI