Time regularity ingredients for the limit stream.
The flow/material estimates of §2 are carried as explicit source-form data; the recursion estimate differentiates the finite-overlap stream update and then applies the mean-value theorem in time.
The canonical smooth periodic flow associated with one member of a stream sequence.
Equations
- AVenhance.constructionFlow hseq m = AVenhance.flow (AVenhance.streamVel (Φ m)) ⋯ ⋯
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The inverse-flow map for constructionFlow, with arguments ordered as in
the flowInv.
Equations
- AVenhance.constructionFlowInv hseq m = AVenhance.flowInv (AVenhance.streamVel (Φ m)) ⋯ ⋯
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The spatial Jacobian of the mth flow at offset t from start time s.
Equations
- AVenhance.constructionFlowJacobian hseq m t s x = fderiv ℝ (fun (y : Homogenization.Vec 2) => AVenhance.constructionFlow hseq m (s + t) y s) x
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The spatial Jacobian of the inverse flow at offset t from start time s.
Equations
- AVenhance.constructionFlowInvJacobian hseq m t s x = fderiv ℝ (fun (y : Homogenization.Vec 2) => AVenhance.constructionFlowInv hseq m (s + t) y s) x
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The forward spatial Jacobian pulled back by its inverse, as in
c.material.DX.Xinv and c.flowreg display 2.
Equations
- AVenhance.constructionComposedFlowJacobian hseq m s r x = AVenhance.constructionFlowJacobian hseq m r s (AVenhance.constructionFlowInv hseq m (s + r) x s)
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Componentwise version of the source spatial seminorm for a matrix field.
Each entry is measured by the scalar barNorm.
Equations
- AVenhance.flowJacobianBarNorm n R J = ⨆ (i : Fin 2), ⨆ (j : Fin 2), AVenhance.barNorm n R fun (x : Homogenization.Vec 2) => (J x) (Homogenization.basisVec j) i
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One material derivative along a time-dependent vector field, matching
D_{t,m} = ∂ₜ + b_m·∇ in the source.
Equations
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Iterates of the source material derivative.
Equations
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Explicit source-form flow and material bounds used in the differentiated
stream recursion. The seminorm fields transcribe e.Xm.regbounds and all four
displays of c.flowreg componentwise; material_jacobian transcribes
c.material.DX.Xinv. The final field records e.PDE.backwards for the inverse
flow.
The source constant in c.material.DX.Xinv is at least one.
- inverse_regbounds (m : ℕ) : 1 ≤ m → ∀ (s t : ℝ), |t| ≤ 2 ^ (-25) * (AVenhance.a β I.Λ m)⁻¹ → ∀ (n : ℕ), (flowJacobianBarNorm n (2 ^ 11 * (epsilon β I.Λ m)⁻¹) fun (x : Homogenization.Vec 2) => constructionFlowInvJacobian hseq m t s x - ContinuousLinearMap.id ℝ (Homogenization.Vec 2)) ≤ ENNReal.ofReal (2 ^ 23 * |t| * AVenhance.a β I.Λ m)
e.Xm.regbounds, componentwise for every derivative order n.
- flow_close (m : ℕ) : 1 ≤ m → ∀ (s t : ℝ), |t| ≤ 2 ^ (-25) * (AVenhance.a β I.Λ m)⁻¹ → ∀ (x : Homogenization.Vec 2), ‖constructionFlowJacobian hseq m t s x - ContinuousLinearMap.id ℝ (Homogenization.Vec 2)‖ ≤ 2 ^ 23 * |t| * AVenhance.a β I.Λ m ∧ 2 ^ 23 * |t| * AVenhance.a β I.Λ m ≤ 1 / 4
c.flowreg display e.Xm.bound.1.
- flow_jacobian_composed (m : ℕ) : 1 ≤ m → ∀ (s t : ℝ), |t| ≤ 2 ^ (-25) * (AVenhance.a β I.Λ m)⁻¹ → ∀ (n : ℕ), (flowJacobianBarNorm n (2 ^ 10 * (epsilon β I.Λ m)⁻¹) fun (x : Homogenization.Vec 2) => constructionComposedFlowJacobian hseq m s t x - ContinuousLinearMap.id ℝ (Homogenization.Vec 2)) ≤ ENNReal.ofReal 40
c.flowreg display e.Xm.bound.2.
- composed_jacobian_smooth (m : ℕ) : 1 ≤ m → ∀ (s t : ℝ), |t| ≤ 2 ^ (-25) * (AVenhance.a β I.Λ m)⁻¹ → ContDiff ℝ ↑⊤ fun (x : Homogenization.Vec 2) => constructionComposedFlowJacobian hseq m s t x
Smooth spatial representative used to evaluate the essential-supremum seminorm bounds pointwise. This is qualitative flow regularity from §2.
- flow_jacobian (m : ℕ) : 1 ≤ m → ∀ (s t : ℝ), |t| ≤ 2 ^ (-25) * (AVenhance.a β I.Λ m)⁻¹ → ∀ (n : ℕ), 1 ≤ n → flowJacobianBarNorm n (2 ^ 14 * (epsilon β I.Λ m)⁻¹) (constructionFlowJacobian hseq m t s) ≤ ENNReal.ofReal 12
c.flowreg display e.Xm.bound.3.
- flow_higher_derivative (m : ℕ) : 1 ≤ m → ∀ (s t : ℝ), |t| ≤ 2 ^ (-25) * (AVenhance.a β I.Λ m)⁻¹ → ∀ (n : ℕ), 1 ≤ n → ∀ (x : Homogenization.Vec 2) (J : Fin n → Fin 2), ‖(iteratedFDeriv ℝ n (fun (y : Homogenization.Vec 2) => constructionFlow hseq m (s + t) y s) x) fun (k : Fin n) => Homogenization.basisVec (J k)‖ ≤ 2 * ↑n.factorial * (2 ^ 14 * (epsilon β I.Λ m)⁻¹) ^ (n - 1)
Corrected c.flowreg derivative bound. The printed radius coefficient
2^13fails at order seven (checked against the source);Scalars.flow_derivative_boundproves the corresponding conversion with2^14. - material_jacobian (m : ℕ) : 1 ≤ m → ∀ (s t : ℝ), |t| ≤ 2 ^ (-25) * (AVenhance.a β I.Λ m)⁻¹ → ∀ (n ell : ℕ), n + ell ≤ Nstar β → ∀ (i j : Fin 2) (x : Homogenization.Vec 2) (J : Fin n → Fin 2), ‖(iteratedFDeriv ℝ n (fun (y : Homogenization.Vec 2) => constructionMaterialIterate (fun (r : ℝ) (z : Homogenization.Vec 2) => streamVel (Φ m) (s + r) z) ell (fun (r : ℝ) (z : Homogenization.Vec 2) => (constructionComposedFlowJacobian hseq m s r z) (Homogenization.basisVec j) i) t y) x) fun (k : Fin n) => Homogenization.basisVec (J k)‖ ≤ Cmat * (epsilon β I.Λ m)⁻¹ ^ n * (epsilon β I.Λ m ^ (β - 2)) ^ ell
c.material.DX.Xinv, in its pointwise derivative form.
- material_jacobian_time_diff (m : ℕ) : 1 ≤ m → ∀ (s t : ℝ), |t| ≤ 2 ^ (-25) * (AVenhance.a β I.Λ m)⁻¹ → ∀ (i j : Fin 2) (x : Homogenization.Vec 2), DifferentiableAt ℝ (fun (r : ℝ) => (constructionComposedFlowJacobian hseq m s r x) (Homogenization.basisVec j) i) t
Classical differentiability in target time of the entries appearing in c.material.DX.Xinv; this is the regularity implicit in that display's partial-time derivatives.
- inverse_jacobian_time_diff (m : ℕ) : 1 ≤ m → ∀ (s t : ℝ) (x : Homogenization.Vec 2), DifferentiableAt ℝ (fun (r : ℝ) => constructionFlowInvJacobian hseq m r s x) t
Classical target-time differentiability of the spatial inverse-flow Jacobian. This is the mixed regularity needed when differentiating the inverse transport equation in space.
- inverse_transport (m : ℕ) : 1 ≤ m → ∀ (t s : ℝ) (x : Homogenization.Vec 2), HasDerivAt (fun (r : ℝ) => constructionFlowInv hseq m r x s) (-(constructionFlowInvJacobian hseq m (t - s) s x) (streamVel (Φ m) t x)) t
e.PDE.backwards for each stream flow.
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Differentiate a transported spatial profile derivative when both the inverse trajectory and its spatial Jacobian have target-time derivatives.
Product rule for the time-dependent cutoff multiplying a transported spatial profile derivative.
The normed-vector mean-value estimate used to turn the differentiated recursion into a time-increment bound.
Rotate a spatial differential to form the velocity of a time increment.
Equations
- AVenhance.timeIncrementRotate L i = if i = 0 then -L (Homogenization.basisVec 1) else L (Homogenization.basisVec 0)