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LeanPool.ArnoldKAM.Arnold1963.Step.FourierDifferential

Supporting results for the analytic Hamiltonian KAM construction.

Pairing with an integer Fourier index as a continuous complex linear functional.

Equations
Instances For
    theorem KamProject.Arnold1963.sum_lowModes_neg {n : ℕ} {A : Type u_1} [AddCommMonoid A] (N : ℝ) (f : FourierIndex n → A) :
    ∑ k ∈ lowModes n N, f (-k) = ∑ k ∈ lowModes n N, f k
    theorem KamProject.Arnold1963.angle_fderiv_eq_sum_qGradient {n : ℕ} {S : ComplexPhaseSpace n → ℂ} {p q : ComplexSpace n} (ha : AnalyticAt ℂ S (p, q)) (v : ComplexSpace n) :
    (fderiv ℂ (fun (t : ComplexSpace n) => S (p, t)) q) v = ∑ j : Fin n, v j * qGradient S (p, q) j