Weighted estimates for actual parameter derivatives of linear ODE solutions #
Parameter derivatives are genuine iterated Fréchet derivatives in prescribed directions. The differentiated Volterra equation gives a triangular system; the energy estimate, rather than an uncontrolled inverse norm, estimates it.
One actual parameter derivative in a fixed direction.
Equations
- NavierStokes.WeightedODEJets.directional f v p = (fderiv ℝ f p) v
Instances For
Successive actual directional Fréchet derivatives. Directions are applied from the head of the word to its tail; the empty word means order zero.
Equations
- NavierStokes.WeightedODEJets.jet f l = List.foldl (fun (g : P → E) (v : P) => NavierStokes.WeightedODEJets.directional g v) f l
Instances For
Restricting all directions to the unit ball converts the estimates to uniform bounds for all mixed parameter derivatives of a given order.
Equations
- NavierStokes.WeightedODEJets.UnitWord l = ∀ v ∈ l, ‖v‖ ≤ 1
Instances For
The word formulation is exactly Mathlib's iterated Fréchet derivative, with the reversal dictated by its convention for the order of arguments.
A bound for the ordinary multilinear derivative controls every word of unit directions, including the empty word.
Unit-direction bounds control the full multilinear norm, also at order zero.
The full Leibniz expansion, retaining ordered differentiation and therefore automatically retaining every mixed-term multiplicity.
Equations
- One or more equations did not get rendered due to their size.
Instances For
The proper Leibniz terms: at least one derivative hits the coefficient, so every solution derivative in this expression has strictly lower order.
Equations
- One or more equations did not get rendered due to their size.
Instances For
Every term in the full Leibniz expansion has the product estimate. There
are 2^length ordered choices of which factor receives each derivative.
The proper Leibniz expansion only requires solution jets of strictly lower order. This is the triangular property used by the weighted induction.
The actual inhomogeneity of the differentiated equation.
Equations
- NavierStokes.WeightedODEJets.jetSource A f u l p = NavierStokes.WeightedODEJets.jet f l p + NavierStokes.WeightedODEJets.crossJet A u l p
Instances For
Every actual parameter jet of the constructed solution is itself the constructed solution of the corresponding triangular variational equation. No existence or smoothness of solution jets is assumed.
The time derivative of each actual parameter jet is its triangular variational equation on the original closed interval.
The constructed solution retains a positive reference envelope. A uniform bound for the error exponential gives a factor linear in the slot length. The estimate follows from the proved energy inequality for the actual ODE.
A finite-order weighted estimate for every actual mixed parameter jet. Only input jets are bounded in the hypotheses. The factor multiplying each successive derivative is polynomial in the slot length and coefficient bound.
A concrete slot-polynomial estimate. w may be a small-scale power times
a slow-variable weight; no loss of its power occurs in the induction.
Actual directional path jets evaluate to the corresponding jets of the jointly supplied coefficient or source at each time.
Jointly smooth physical inputs with polynomial bounds on their actual Fréchet jets give polynomially bounded jets of the actual ODE solution. The bound is for the full multilinear norm at each time, retaining the envelope.