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BGW.Skorokhod.VervaatWindowApproximation

Path estimates for the local window correction #

The source and corrected source times remain near the minimum inside the window. Outside it the original approximation is preserved exactly.

theorem BGW.Skorokhod.exists_aligned_timeChange (u f : D 1 ℝ) (σ : TimeChange 1) (g a : ↑(Set.Icc 0 1)) {η d e : ℝ} (hη : 0 < η) (hleft : η ≤ ↑g) (hright : ↑g + η ≤ 1) (hnear : dist ((OrderIso.symm σ) a) g < η) (hd : ∀ (t : ↑(Set.Icc 0 1)), |↑(σ t) - ↑t| ≤ d) (hp : ∀ (t : ↑(Set.Icc 0 1)), dist (u (σ t)) (f t) ≤ e) (hf : ∀ (s : ↑(Set.Icc 0 1)), dist s g < 2 * η → dist (f s) (f g) ≤ e) :
∃ (ρ : TimeChange 1), ρ g = a ∧ (∀ (t : ↑(Set.Icc 0 1)), |↑(ρ t) - ↑t| ≤ d + η) ∧ ∀ (t : ↑(Set.Icc 0 1)), dist (u (ρ t)) (f t) ≤ 3 * e

Align one time by a local correction, paying only the oscillation in its window.