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LeanPool.HighContrastHomogenization.Analytic.AffineH1a0

High-contrast homogenization: Analytic.AffineH1a0 #

Imported from the Apache-2.0 HighContrastHomogenization development at commit 7a13dbcd8d6609264a713373f5c69ceeac870472.

Affine transport of coefficient-weighted zero-trace data #

An invertible linear pullback transports the complete H¹_{a,0} class. The compactly supported approximants are composed with the matrix map, while their gradients and the limiting weak gradient transform by the transpose matrix.

theorem HCPolySupport.HighContrast.memH1a0_affinePullback {d : ℕ} {L : Mat d} (hL : IsUnit (Matrix.det L)) {U : Set (Vec d)} (hU : MeasurableSet U) {b : CoeffField d} {lam Lam : ℝ} (hlam : 0 < lam) (hell : ∀ᵐ (x : Vec d), IsEllipticMatrix lam Lam (b x)) (hUfin : MeasureTheory.volume U ≠ ⊤) {u : Vec d → ℝ} {Du : Vec d → Vec d} (hu : MemH1a0 b U u Du) :
MemH1a0 (affineCoefficient L hL b) (matImage L⁻¹ U) (fun (y : Vec d) => u (matVecMul L y)) fun (y : Vec d) => matVecMul (matTranspose L) (Du (matVecMul L y))

The coefficient-weighted zero-trace class is covariant under every invertible linear change of variables.