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LeanPool.CIVAxisymmetric.Zoom.VLipschitz

Lipschitz-in-space bound for the finite-axis rescaled radial field #

An input to the Arzelà–Ascoli extraction in Step 2 of the proof of prop:aniso:small (eq:aniso:zoom:finite:compactness): on a rectangle [Ra, Rb] × [Za, Zb] contained in the unit cylinder (via hmem), the finite-axis rescaled radial field V_n of eq:aniso:zoom:finite:variables is Lipschitz in the spatial variables, with a τ-independent constant 2C.

The proof follows CIV.Zoom.VRecLipschitz's two-edge mean-value-inequality route: on each coordinate edge of the rectangle, Convex.norm_image_sub_le_of_norm_hasDerivWithin_le applied to the per-point derivative bounds from abs_dr_zoomV_le_rpow_neg_half and abs_dz_zoomV_le_rpow_neg_half gives a τ-uniform bound; the two edges are combined by the triangle inequality.

theorem CIV.lipschitzOnWith_zoomV {C h lam zc Ra Rb Za Zb tau : ℝ} (hlam : 0 < lam) {u : CKN.Foundation.Parabolic.ParabolicPoint → CKN.Foundation.Parabolic.Vec3} (hb : AnisotropicBounds C h u) (hu : ContDiffOn ℝ 2 (fun (z : CKN.Foundation.Parabolic.Vec3 × ℝ) => u z) unitCylinder) (hC : 0 ≤ C) (hh1 : h ≤ 1 / 2) (htau : tau ≤ -1) (hmem : ∀ y ∈ Set.Icc Ra Rb ×ˢ Set.Icc Za Zb, zoomPoint lam h zc (y, tau) ∈ unitCylinder) :
LipschitzOnWith (2 * C).toNNReal (fun (y : ℝ × ℝ) => zoomV lam h zc u (y, tau)) (Set.Icc Ra Rb ×ˢ Set.Icc Za Zb)