Derivative data under parabolic scaling #
The weak derivative fields of lem:uc-gaussian transform with one or two
powers of the spatial scale.
theorem
ESS.uc_scaled_weak_heat
(x₀ : CKN.Foundation.Parabolic.Vec3)
(scale : ℝ)
(D2w : CKN.Foundation.Parabolic.ParabolicPoint → Fin 3 → Fin 3 → CKN.Foundation.Parabolic.Vec3)
(Dtw : CKN.Foundation.Parabolic.ParabolicPoint → CKN.Foundation.Parabolic.Vec3)
(z : CKN.Foundation.Parabolic.ParabolicPoint)
:
ucWeakHeatVector (ucScaledD2w x₀ scale D2w) (ucScaledDtw x₀ scale Dtw) z = scale ^ 2 • ucWeakHeatVector D2w Dtw (ucScaledPoint x₀ scale z)
The specified weak heat vector scales by the square of the parabolic spatial scale.
theorem
ESS.uc_scaled_gradient_sq
(x₀ : CKN.Foundation.Parabolic.Vec3)
(scale : ℝ)
(w : CKN.Foundation.Parabolic.ParabolicPoint → CKN.Foundation.Parabolic.Vec3)
(Dw : CKN.Foundation.Parabolic.ParabolicPoint → Fin 3 → CKN.Foundation.Parabolic.Vec3)
(z : CKN.Foundation.Parabolic.ParabolicPoint)
:
CKN.spatialGradientSq (ucScaledField x₀ scale w) (ucScaledDw x₀ scale Dw) z = scale ^ 2 * CKN.spatialGradientSq w Dw (ucScaledPoint x₀ scale z)
The squared spatial gradient scales by the square of the spatial scale.
theorem
ESS.uc_scaled_weak_heat_bound
(x₀ : CKN.Foundation.Parabolic.Vec3)
(scale c₁ : ℝ)
(hscale : 0 < scale)
(hscale1 : scale ≤ 1)
(hc₁ : 0 ≤ c₁)
(w : CKN.Foundation.Parabolic.ParabolicPoint → CKN.Foundation.Parabolic.Vec3)
(Dw : CKN.Foundation.Parabolic.ParabolicPoint → Fin 3 → CKN.Foundation.Parabolic.Vec3)
(D2w : CKN.Foundation.Parabolic.ParabolicPoint → Fin 3 → Fin 3 → CKN.Foundation.Parabolic.Vec3)
(Dtw : CKN.Foundation.Parabolic.ParabolicPoint → CKN.Foundation.Parabolic.Vec3)
(z : CKN.Foundation.Parabolic.ParabolicPoint)
(hineq :
CKN.Foundation.Parabolic.vec3EuclideanNorm (ucWeakHeatVector D2w Dtw (ucScaledPoint x₀ scale z)) ≤ c₁ * (CKN.Foundation.Parabolic.vec3EuclideanNorm (w (ucScaledPoint x₀ scale z)) + √(CKN.spatialGradientSq w Dw (ucScaledPoint x₀ scale z))))
:
CKN.Foundation.Parabolic.vec3EuclideanNorm (ucWeakHeatVector (ucScaledD2w x₀ scale D2w) (ucScaledDtw x₀ scale Dtw) z) ≤ c₁ * scale * (CKN.Foundation.Parabolic.vec3EuclideanNorm (ucScaledField x₀ scale w z) + √(CKN.spatialGradientSq (ucScaledField x₀ scale w) (ucScaledDw x₀ scale Dw) z))
The differential inequality keeps its form under a subunit parabolic scale, with coefficient multiplied by that scale.