OAI/Geometry/SurfaceImmersion/Primitive/PerturbedCircularCutoffs.lean
5 declarations, 0 contain sorry, 0 declared as axioms
Actual independent radius perturbations of circular manifold cutoffs. A fixed larger disk supplies common support and uniform continuity.
- lemma
OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularCoordinateRegion_monoline 16 - lemma
OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularDiskClosure_monoline 22 - lemma
OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularManifoldBump_zero_off_larger_diskline 27 - lemma
OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularManifoldBump_joint_continuousAtline 42Source documentation
The radius and base point vary continuously together, including at the chart boundary where the common compact support forces the cutoff to vanish.
lemma circularManifoldBump_joint_continuousAt (p : M) {R r : ℝ} (hregion : circularCoordinateRegion p R ⊆ (coordinateChart p).target) (hr : |r| < R) (x : M) : ContinuousAt (fun z : ℝ × M => circularManifoldBump p z.1 z.2) (r,x) := by …Mentions: OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularCoordinateRegion, OAI.ClosedSurfaceR4.coordinateChart, OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularManifoldBump
- theorem
OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularManifoldBump_uniform_perturbationline 79Source documentation
Moving one radius slightly gives an actual smooth cutoff with one fixed compact support and arbitrarily small global C0 error. The radius may be chosen independently for each member of a later finite family.
theorem circularManifoldBump_uniform_perturbation (p : M) {R r : ℝ} (hregion : circularCoordinateRegion p R ⊆ (coordinateChart p).target) (hr : |r| < R) {eps : ℝ} (heps : 0 < eps) : ∃ delta : ℝ, 0 < delta ∧ ∀ r' : ℝ, |r'-r| < delta → |r'| < R ∧ ContMDiff planeModel 𝓘(ℝ) ∞ (circularManifoldBump p r') ∧ tsupport (circularManifoldBump p r') ⊆ circularDiskClosure p R ∧ ∀ x : M, |circularManifoldBump p r' x-circularManifoldBump p r x| < eps := by …Mentions: OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularCoordinateRegion, OAI.ClosedSurfaceR4.coordinateChart, OAI.ClosedSurfaceR4.planeModel, OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularManifoldBump, OAI.ClosedSurfaceR4.FiniteOrderSmoothing.circularDiskClosure