OAI/Geometry/SurfaceImmersion/Correction/SmoothingC1Approximation.lean
3 declarations, 0 contain sorry, 0 declared as axioms
Uniform approximation of C1 coordinate maps by the existing smooth kernel.
- lemma
OAI.ClosedSurfaceR4.FiniteOrderSmoothing.fderiv_smooth_C1line 16 - theorem
OAI.ClosedSurfaceR4.FiniteOrderSmoothing.smooth_uniform_approximationline 32Source documentation
Uniform continuity suffices for uniform convergence of the signed finite-moment kernel. Positivity of the kernel is not required.
theorem smooth_uniform_approximation (r : ℕ) {f : Base → E} (hf : UniformContinuous f) {ε : ℝ} (hε : 0 < ε) : ∃ η : ℝ, 0 < η ∧ ∀ s : ℝ, 0 < s → s < η → ∀ x : Base, ‖smooth r s f x-f x‖ ≤ ε := by … - theorem
OAI.ClosedSurfaceR4.FiniteOrderSmoothing.smooth_C1_approximationline 85Source documentation
Compactly supported C1 maps have smooth approximants converging uniformly both as maps and in their first derivatives.
theorem smooth_C1_approximation (r : ℕ) {f : Base → E} (hf : ContDiff ℝ 1 f) (hfc : HasCompactSupport f) {ε : ℝ} (hε : 0 < ε) : ∃ η : ℝ, 0 < η ∧ ∀ s : ℝ, 0 < s → s < η → ContDiff ℝ ∞ (smooth r s f) ∧ ∀ x, ‖smooth r s f x-f x‖ ≤ ε ∧ ‖fderiv ℝ (smooth r s f) x-fderiv ℝ f x‖ ≤ ε := by …