The L² composition estimate over an arbitrary measure space. This version allows the base to be a periodic cylinder while the derivatives are tensors on its Euclidean cover. The output is the literal finite Taylor composition of the given jets.
theorem
EulerGevreyJetCompositionLp.taylorComp_partition_bound
{E : Type u_2}
{F : Type u_3}
[NormedAddCommGroup E]
[NormedSpace ℝ E]
[NormedAddCommGroup F]
[NormedSpace ℝ F]
(P : FormalMultilinearSeries ℝ E E)
(Q : FormalMultilinearSeries ℝ E F)
(n : ℕ)
(B R : ℝ)
(hP : ∀ (j : ℕ), 0 < j → j ≤ n → ‖P j‖ ≤ B * R ^ j * ↑j.factorial ^ 2)
:
‖Q.taylorComp P n‖ ≤ ∑ c : OrderedFinpartition n, EulerGevreyCompositionLp.innerPartitionBound B R c * ‖Q c.length‖
theorem
EulerGevreyJetCompositionLp.composition_memLp_and_bound
{X : Type u_1}
{E : Type u_2}
{F : Type u_3}
[MeasurableSpace X]
[NormedAddCommGroup E]
[NormedSpace ℝ E]
[NormedAddCommGroup F]
[NormedSpace ℝ F]
(μ : MeasureTheory.Measure X)
(φ : X → X)
(hφ : MeasureTheory.MeasurePreserving φ μ μ)
(P : X → FormalMultilinearSeries ℝ E E)
(Q : X → FormalMultilinearSeries ℝ E F)
(n : ℕ)
(hcomp : MeasureTheory.AEStronglyMeasurable (fun (x : X) => (Q (φ x)).taylorComp (P x) n) μ)
(A B R S : ℝ)
(hA : 0 ≤ A)
(hB : 0 ≤ B)
(hR : 0 ≤ R)
(hS : 0 ≤ S)
(hQLp : ∀ j ≤ n, MeasureTheory.MemLp (fun (x : X) => Q x j) 2 μ)
(hQ : ∀ j ≤ n, (MeasureTheory.eLpNorm (fun (x : X) => Q x j) 2 μ).toReal ≤ A * S ^ j * ↑j.factorial ^ 2)
(hP : ∀ (j : ℕ), 0 < j → j ≤ n → ∀ (x : X), ‖P x j‖ ≤ B * R ^ j * ↑j.factorial ^ 2)
:
MeasureTheory.MemLp (fun (x : X) => (Q (φ x)).taylorComp (P x) n) 2 μ ∧ (MeasureTheory.eLpNorm (fun (x : X) => (Q (φ x)).taylorComp (P x) n) 2 μ).toReal ≤ A * (R * (B * S + 2)) ^ n * ↑n.factorial ^ 2
Outer tensors are transported in L² by the actual measure-preserving map; only the positive inner tensors use uniform bounds.