Initial ball from the Gaussian estimate #
The box estimate in lem:uc-gaussian and continuity at time zero force the
trace to vanish on its output ball.
theorem
ESS.uc_initial_ball_vanishing
(R T : ℝ)
(hR : 0 < R)
(hT : 0 < T)
(x₀ : CKN.Foundation.Parabolic.Vec3)
(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)
(hcont : ContinuousOn w (CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball x₀ R) (Set.Ico 0 T)))
(hweak : CKN.HasSpaceTimeWeakDerivs (CKN.Foundation.Parabolic.vec3Ball x₀ R) (Set.Ioo 0 T) w Dw D2w Dtw)
(hL2 :
∫⁻ (z : CKN.Foundation.Parabolic.ParabolicPoint) in CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball x₀ R) (Set.Ioo 0 T), ‖w z‖ₑ ^ 2 + ‖Dw z‖ₑ ^ 2 + ‖D2w z‖ₑ ^ 2 + ‖Dtw z‖ₑ ^ 2 < ⊤)
(hzero : w (x₀, 0) = 0)
(hgauss :
∃ (γ : ℝ) (C : ℝ),
0 < γ ∧ γ < 3 / 16 ∧ 0 < C ∧ ∀ (x : CKN.Foundation.Parabolic.Vec3) (t : ℝ),
0 < t →
t ≤ γ * T →
CKN.Foundation.Parabolic.vec3EuclideanNorm (x - x₀) ≤ ucRadiusFraction * R →
16 / 100 * t ≤ CKN.Foundation.Parabolic.vec3EuclideanNorm (x - x₀) ^ 2 →
∫ (z : CKN.Foundation.Parabolic.ParabolicPoint) in CKN.spaceTimeSet (CKN.Foundation.Parabolic.vec3Ball x √(2 * t)) (Set.Ioo t (2 * t)), CKN.Foundation.Parabolic.vec3EuclideanNorm (w z) ^ 2 ≤ C * ucLocalEnergy x₀ R T w Dw * Real.exp (-CKN.Foundation.Parabolic.vec3EuclideanNorm (x - x₀) ^ 2 / (2 * t)))
(x : CKN.Foundation.Parabolic.Vec3)
:
x ∈ CKN.Foundation.Parabolic.vec3Ball x₀ (ucRadiusFraction * R) → w (x, 0) = 0
A Gaussian box estimate propagates a zero initial trace from its center
to the entire inner output ball (thm:uc).