The blow-up limit #
prop:blowup-limit in the form used by the proof of thm:ess-local:
at a point that is not good, every sequence of scales tending to zero has a
blow-up limit that is a suitable weak solution on every bounded past
cylinder, has weak spatial gradients on almost every slice, lies in
L^∞((-T,0); L³) for every T, has a pressure in L^(3/2) on every past slab,
has zero terminal trace, and cannot vanish on the past of the unit cylinder
(the bad-point lower bound).
theorem
ESS.blowupLimit_projection
{u : CKN.Foundation.Parabolic.ParabolicPoint → CKN.Foundation.Parabolic.Vec3}
{Du : CKN.Foundation.Parabolic.ParabolicPoint → Fin 3 → CKN.Foundation.Parabolic.Vec3}
{p : CKN.Foundation.Parabolic.ParabolicPoint → ℝ}
(hu :
MeasureTheory.AEStronglyMeasurable u
(MeasureTheory.volume.restrict (CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball 0 1) (Set.Ioo (-1) 0))))
(hDu :
MeasureTheory.AEStronglyMeasurable Du
(MeasureTheory.volume.restrict (CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball 0 1) (Set.Ioo (-1) 0))))
(hp :
MeasureTheory.AEStronglyMeasurable p
(MeasureTheory.volume.restrict (CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball 0 1) (Set.Ioo (-1) 0))))
(hL2 :
essSup
(fun (t : ℝ) => ∫⁻ (x : CKN.Foundation.Parabolic.Vec3) in CKN.Foundation.Parabolic.vec3Ball 0 1, ‖u (x, t)‖ₑ ^ 2)
(MeasureTheory.volume.restrict (Set.Ioo (-1) 0)) < ⊤)
(henergy :
∫⁻ (z : CKN.Foundation.Parabolic.ParabolicPoint) in CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball 0 1) (Set.Ioo (-1) 0), ‖u z‖ₑ ^ 2 + ‖Du z‖ₑ ^ 2 < ⊤)
(hpLp :
MeasureTheory.MemLp p (ENNReal.ofReal (3 / 2))
(MeasureTheory.volume.restrict (CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball 0 1) (Set.Ioo (-1) 0))))
(hL3 :
essSup
(fun (t : ℝ) =>
∫⁻ (x : CKN.Foundation.Parabolic.Vec3) in CKN.Foundation.Parabolic.vec3Ball 0 1, ENNReal.ofReal (CKN.Foundation.Parabolic.vec3EuclideanNorm (u (x, t))) ^ 3)
(MeasureTheory.volume.restrict (Set.Ioo (-1) 0)) < ⊤)
(hgrad :
∀ᵐ (t : ℝ) ∂MeasureTheory.volume.restrict (Set.Ioo (-1) 0), ∀ (i : Fin 3),
CKN.HasWeakGradientOn (CKN.Foundation.Parabolic.vec3Ball 0 1) (fun (x : CKN.Vec 3) => u (x, t) i)
fun (x : CKN.Vec 3) => Du (x, t) i)
(hS2 :
∀ ψ ∈ CKN.spaceTimeTestFunction (CKN.Foundation.Parabolic.vec3Ball 0 1) (Set.Ioo (-1) 0),
∫ (z : CKN.Foundation.Parabolic.ParabolicPoint) in CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball 0 1) (Set.Ioo (-1) 0), ∑ i : Fin 3, u z i * CKN.spatialPartial ψ i z = 0)
(hS3 :
∀ φ ∈ CKN.spaceTimeTestFunction (CKN.Foundation.Parabolic.vec3Ball 0 1) (Set.Ioo (-1) 0),
∫ (z : CKN.Foundation.Parabolic.ParabolicPoint) in CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball 0 1) (Set.Ioo (-1) 0), -∑ i : Fin 3, u z i * CKN.timePartial (fun (y : CKN.Foundation.Parabolic.ParabolicPoint) => φ y i) z - ∑ i : Fin 3,
∑ j : Fin 3,
u z i * u z j * CKN.spatialPartial (fun (y : CKN.Foundation.Parabolic.ParabolicPoint) => φ y i) j z + ∑ i : Fin 3,
∑ j : Fin 3,
Du z i j * CKN.spatialPartial (fun (y : CKN.Foundation.Parabolic.ParabolicPoint) => φ y i) j z - p z * ∑ i : Fin 3, CKN.spatialPartial (fun (y : CKN.Foundation.Parabolic.ParabolicPoint) => φ y i) i z - ∑ i : Fin 3, 0 z i * φ z i = 0)
(ε₀ : ℝ)
:
0 < ε₀ →
∀ (x₀ : CKN.Foundation.Parabolic.Vec3) (t₀ : ℝ) (r : ℕ → ℝ),
x₀ ∈ closure (CKN.Foundation.Parabolic.vec3Ball 0 (1 / 2)) →
t₀ ∈ Set.Icc (-(1 / 4)) 0 →
¬IsGoodPoint ε₀ u p (x₀, t₀) →
(∀ (k : ℕ), 0 < r k) →
Filter.Tendsto r Filter.atTop (nhds 0) →
∃ (U : CKN.Foundation.Parabolic.ParabolicPoint → CKN.Foundation.Parabolic.Vec3) (DU :
CKN.Foundation.Parabolic.ParabolicPoint → Fin 3 → CKN.Foundation.Parabolic.Vec3) (q :
CKN.Foundation.Parabolic.ParabolicPoint → ℝ),
Measurable U ∧ (∀ (R a : ℝ),
0 < R →
a < 0 →
CKN.IsSuitableWeakSolution (CKN.Foundation.Parabolic.vec3Ball 0 R) (Set.Ioo a 0) 3 U DU q 0) ∧ (∀ᵐ (t : ℝ) ∂MeasureTheory.volume.restrict (Set.Ioo (-2) 0), ∀ (i : Fin 3),
CKN.HasWeakGradientOn Set.univ (fun (x : CKN.Foundation.Parabolic.Vec3) => U (x, t) i)
fun (x : CKN.Foundation.Parabolic.Vec3) => DU (x, t) i) ∧ (∀ (T : ℝ),
0 < T →
essSup
(fun (t : ℝ) =>
MeasureTheory.eLpNorm
(fun (x : CKN.Foundation.Parabolic.Vec3) =>
CKN.Foundation.Parabolic.vec3EuclideanNorm (U (x, t)))
3 MeasureTheory.volume)
(MeasureTheory.volume.restrict (Set.Ioo (-T) 0)) < ⊤) ∧ (∀ (T : ℝ),
0 < T →
MeasureTheory.MemLp q (3 / 2)
(MeasureTheory.volume.restrict (CKN.spaceTimeSet Set.univ (Set.Ioo (-T) 0)))) ∧ HasZeroDistributionalVelocityTrace U ∧ (U =ᵐ[MeasureTheory.volume.restrict (CKN.spaceTimeSet Set.univ (Set.Ioo (-2) 0))] 0 →
Filter.Tendsto
(fun (k : ℕ) =>
goodPointEnergy (blowupVelocity x₀ t₀ (r k) u) (blowupPressure x₀ t₀ (r k) p) 0 0 1)
Filter.atTop (nhds 0))
The blow-up limit at a point that is not good (prop:blowup-limit),
under the hypotheses of thm:ess-local.