Uniform comparison of ideal primary sizes before target. This follows from the actual scalar equation's prefix and weighted monotonicity.
theorem
EulerPacketMovingFrame.equation30_polynomial_size_monotone
{σ : ℝ}
{Z Z₁ : ℝ → ℝ}
(hσ : 0 < σ)
(hσsmall : σ ≤ 1 / 4)
(hZ : ∀ (t : ℝ), 0 ≤ t → HasDerivAt Z (Z₁ t) t)
(hfluxZ :
∀ (t : ℝ),
0 ≤ t → HasDerivAt (fun (s : ℝ) => (1 + (σ ^ 2 * s ^ 2) ^ 2) * Z₁ s) (2 * (1 - σ ^ 2 * (σ ^ 2 * t ^ 2)) * Z t) t)
(hZ0 : Z 0 = 1)
(hZ₁0 : 0 ≤ Z₁ 0)
:
theorem
EulerPacketMovingFrame.equation30_ideal_size_comparison
{σ s t : ℝ}
{Z Z₁ : ℝ → ℝ}
(hσ : 0 < σ)
(hσsmall : σ ≤ 1 / 4)
(hZ : ∀ (t : ℝ), 0 ≤ t → HasDerivAt Z (Z₁ t) t)
(hfluxZ :
∀ (t : ℝ),
0 ≤ t → HasDerivAt (fun (s : ℝ) => (1 + (σ ^ 2 * s ^ 2) ^ 2) * Z₁ s) (2 * (1 - σ ^ 2 * (σ ^ 2 * t ^ 2)) * Z t) t)
(hZ0 : Z 0 = 1)
(hZ₁0 : 0 ≤ Z₁ 0)
(hs : 0 ≤ s)
(hst : s ≤ t)
:
The ideal physical primary size is bounded by twice its later size, uniformly in the initial nonnegative scalar slope.