The estimate for on compactly supported maps
ProvedCauchyRiemannIndex.plane_cauchyRiemann_estimateLet and , and let be the standard complex structure on . There is a constant such that every continuously differentiable map with compact support satisfies
where are the coordinates of and the measure is Lebesgue measure.
This is the basic elliptic estimate for the Cauchy–Riemann operator in real notation, in the form used for linear Cauchy–Riemann type operators on Riemann surfaces and cylinders (Wendl, Lecture 4).
Formalization Note. is EuclideanSpace ℝ (Fin n ⊕ Fin n), is Matrix.J, acting through Matrix.toEuclideanLin. Points of the plane are pairs ; and are partialS v x = fderiv ℝ v x (1, 0) and partialT v x = fderiv ℝ v x (0, 1). means ContDiff ℝ 1. Norms are eLpNorm with values in , for an exponent p : ℝ≥0∞ with and . The constant is chosen before ; the measure on is volume.
import Definitions.Def_CauchyRiemannIndex_Setting import Mathlib.Analysis.Calculus.ContDiff.Basic
namespace CauchyRiemannIndex
open MeasureTheory Matrix
open scoped ENNReal NNReal
/-- For `1 < p < ∞` there is `A` such that every `C¹` map `v : ℝ × ℝ → ℝ²ⁿ` with compact support
satisfies `‖∂ₛv‖_p + ‖∂ₜv‖_p ≤ A ‖∂ₛv + J₀ ∂ₜv‖_p` on the plane. -/
theorem plane_cauchyRiemann_estimate (n : ℕ) (p : ℝ≥0∞) (hp : 1 < p) (hp' : p ≠ ⊤) :
∃ A : ℝ≥0, ∀ v : ℝ × ℝ → Vec n, ContDiff ℝ 1 v → HasCompactSupport v →
eLpNorm (partialS v) p volume + eLpNorm (partialT v) p volume ≤
A * eLpNorm (fun x => partialS v x + Matrix.toEuclideanLin (J₀ n) (partialT v x)) p volume := by
sorry
end CauchyRiemannIndex