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LeanPool.ViscositySolutionTheory.AleksandrovDifferentiability.Analysis.Directional.Reconstruction

Ported for Lean Pool: imports relocated and code adapted to Lean/Mathlib v4.34.0.

Reconstruction from directional quadratic data #

This file converts mixed directional quadratic estimate data into the project-local second-order differentiability predicate.

Mixed-directional quadratic estimate data implies second-order differentiability.

Mixed-directional quadratic quotient data implies second-order differentiability.

Polarized coefficient estimate data is a special case of mixed-directional estimate data.

Punctured normalized polarized coefficient estimate data is a special case of mixed-directional quotient estimate data.

Polarized mixed-directional estimate data implies second-order differentiability.

Polarized mixed-directional quotient estimate data implies second-order differentiability.

theorem AleksandrovDifferentiability.polarizedMixedDirectionalQuadraticEstimateAt_of_quadraticEstimateData_coefficients {E : Type u_1} [NormedAddCommGroup E] [InnerProductSpace ℝ E] {ι : Type u_2} [DecidableEq ι] {D : Finset ι} {v : ι → E} (hv : FiniteOrthonormalSpanningOn D v) {u : E → ℝ} {x p : E} {B : E →L[ℝ] E} (hB : IsSymmetricOperator B) {q : ι → ℝ} {r : ι → ι → ℝ} (hest : ∀ (ε : ℝ), 0 < ε → ∀ᶠ (z : E) in nhds 0, ‖affineRemainder u x p (x + z) - 1 / 2 * inner ℝ z (B z)‖ ≤ ε * ‖z‖ ^ 2) (hr : ∀ ⦃i : ι⦄, i ∈ D → ∀ ⦃j : ι⦄, j ∈ D → r j i = r i j) (hpure : ∀ ⦃i : ι⦄, i ∈ D → inner ℝ (v i) (B (v i)) = q i) (hpair : ∀ ⦃i : ι⦄, i ∈ D → ∀ ⦃j : ι⦄, j ∈ D → i ≠ j → inner ℝ (v i + v j) (B (v i + v j)) = r i j) :

If a symmetric ambient quadratic estimate has the prescribed pure and off-diagonal pairwise-sum quadratic coefficients on a finite orthonormal spanning frame, then it is the canonical polarized mixed-directional estimate. The algebraic identification of the Hessian candidate is handled by finite-frame off-diagonal uniqueness.

theorem AleksandrovDifferentiability.polarizedMixedDirectionalQuadraticQuotientEstimateAt_of_quadraticQuotientData_coefficients {E : Type u_1} [NormedAddCommGroup E] [InnerProductSpace ℝ E] {ι : Type u_2} [DecidableEq ι] {D : Finset ι} {v : ι → E} (hv : FiniteOrthonormalSpanningOn D v) {u : E → ℝ} {x p : E} {B : E →L[ℝ] E} (hB : IsSymmetricOperator B) {q : ι → ℝ} {r : ι → ι → ℝ} (hest : ∀ (ε : ℝ), 0 < ε → ∀ᶠ (z : E) in nhdsWithin 0 {z : E | z ≠ 0}, ‖affineRemainder u x p (x + z) - 1 / 2 * inner ℝ z (B z)‖ / ‖z‖ ^ 2 ≤ ε) (hr : ∀ ⦃i : ι⦄, i ∈ D → ∀ ⦃j : ι⦄, j ∈ D → r j i = r i j) (hpure : ∀ ⦃i : ι⦄, i ∈ D → inner ℝ (v i) (B (v i)) = q i) (hpair : ∀ ⦃i : ι⦄, i ∈ D → ∀ ⦃j : ι⦄, j ∈ D → i ≠ j → inner ℝ (v i + v j) (B (v i + v j)) = r i j) :

Punctured normalized quotient version of polarizedMixedDirectionalQuadraticEstimateAt_of_quadraticEstimateData_coefficients.

A local mixed-directional estimate gives the punctured normalized quotient estimate with the same directional coefficient matrix.

A local polarized mixed-directional estimate gives the punctured normalized quotient estimate with the same pure and pairwise-sum coefficients.

Mixed-directional quadratic estimate data is ambient quadratic estimate data with the assembled mixed-directional Hessian candidate.

Mixed-directional quotient estimate data is ambient quadratic quotient estimate data with the assembled mixed-directional Hessian candidate.

Polarized mixed-directional quadratic estimate data is ambient quadratic estimate data.

Polarized mixed-directional quotient estimate data is ambient quadratic quotient estimate data.

The mixed-directional estimate set is contained in the second-order differentiability locus.

The mixed-directional quotient-estimate set is contained in the second-order differentiability locus.

The polarized mixed-directional estimate set is contained in the mixed-directional estimate set.

The polarized mixed-directional quotient estimate set is contained in the mixed-directional quotient estimate set.

The local mixed-directional estimate set is contained in its punctured normalized quotient version.

The local polarized mixed-directional estimate set is contained in its punctured normalized quotient version.

The mixed-directional estimate set is contained in the generic ambient quadratic estimate set.

The mixed-directional quotient-estimate set is contained in the generic ambient quadratic quotient-estimate set.

The polarized mixed-directional estimate set is contained in the generic ambient quadratic estimate set.

The polarized mixed-directional quotient-estimate set is contained in the generic ambient quadratic quotient-estimate set.

The polarized mixed-directional estimate set is contained in the second-order differentiability locus.

The polarized mixed-directional quotient estimate set is contained in the second-order differentiability locus.

Mixed-directional quadratic estimate data restricts to scalar quadratic estimate data on every affine line through the base point.

Mixed-directional quadratic estimate data restricts to scalar quadratic estimate data with the line slope and quadratic coefficient specified by the ambient data.

Mixed-directional punctured quotient estimate data restricts to scalar quadratic estimate data on every affine line through the base point.

Mixed-directional punctured quotient estimate data restricts to explicit scalar quotient estimate data with the line slope and quadratic coefficient specified by the ambient data.

Mixed-directional quadratic estimate data restricts to punctured scalar quotient-estimate data on every affine line through the base point.

Mixed-directional punctured quotient estimate data restricts to punctured scalar quotient-estimate data on every affine line through the base point.

Mixed-directional quadratic estimate data implies the finite slice-estimate target for the selected directions and their pairwise sums.

Mixed-directional quadratic estimate data implies compatible finite slice data: all one-dimensional first-order coefficients come from the same ambient slope.

Mixed-directional quadratic estimate data implies symmetric-compatible finite slice data. The pairwise coefficients are read directly from the ambient quadratic model, so reversing the order of the two selected directions does not change them.

Mixed-directional quadratic estimate data implies the finite slice quotient-estimate target for the selected directions and their pairwise sums.

Mixed-directional quotient estimate data implies the finite slice-estimate target for the selected directions and their pairwise sums.

Mixed-directional quotient estimate data implies compatible finite quotient-slice data.

Mixed-directional quotient estimate data implies symmetric-compatible finite quotient-slice data.

Mixed-directional quotient estimate data implies the finite slice quotient-estimate target for the selected directions and their pairwise sums.

Polarized mixed-directional quadratic estimate data implies the finite slice-estimate target for the selected directions and their pairwise sums.

Polarized mixed-directional quadratic estimate data implies compatible finite slice data.

Polarized mixed-directional quadratic estimate data implies symmetric-compatible finite slice data.

Polarized mixed-directional quadratic estimate data implies the finite slice quotient target for the selected directions and their pairwise sums.

Polarized mixed-directional quotient estimate data implies the finite slice-estimate target for the selected directions and their pairwise sums.

Polarized mixed-directional quotient estimate data implies compatible finite quotient-slice data.

Polarized mixed-directional quotient estimate data implies symmetric-compatible finite quotient-slice data.

Polarized mixed-directional quotient estimate data implies the finite slice quotient target for the selected directions and their pairwise sums.

Compatible finite slice data forgets to the existential finite slice target.

Symmetric compatible finite slice data forgets to compatible finite slice data.

Compatible finite slice data can be represented with symmetric pairwise-sum coefficients by averaging the two ordered pair coefficients.

Compatible finite quotient-slice data forgets to the existential finite quotient-slice target.

Symmetric compatible finite quotient-slice data forgets to compatible finite quotient-slice data.

Compatible finite quotient-slice data can be represented with symmetric pairwise-sum coefficients by averaging the two ordered pair coefficients.

Compatible finite slice data gives compatible finite quotient-slice data with the same ambient slope and scalar quadratic coefficients.

Symmetric compatible finite slice data gives symmetric compatible finite quotient-slice data with the same ambient slope and scalar quadratic coefficients.

Points with mixed-directional estimate data restrict to scalar estimate points on every affine line through the base point.

Points with mixed-directional quotient estimate data restrict to scalar quotient-estimate points on every affine line through the base point.

The mixed-directional estimate set is contained in the finite directional slice-estimate set.

The mixed-directional estimate set is contained in the compatible finite slice-estimate set.

The mixed-directional estimate set is contained in the symmetric-compatible finite slice-estimate set.

The compatible finite slice-estimate set is contained in the symmetric compatible finite slice-estimate set.

theorem AleksandrovDifferentiability.directionalSliceEstimateAt_of_pure_offDiagonal {E : Type u_1} [NormedAddCommGroup E] [InnerProductSpace ℝ E] {ι : Type u_2} {D : Finset ι} {v : ι → E} {u : E → ℝ} {x : E} (hpure : ∀ ⦃i : ι⦄, i ∈ D → RealScalarQuadraticEstimateAt (lineRestriction u x (v i)) 0) (hpair : ∀ ⦃i : ι⦄, i ∈ D → ∀ ⦃j : ι⦄, j ∈ D → i ≠ j → RealScalarQuadraticEstimateAt (lineRestriction u x (v i + v j)) 0) :

Pure directional scalar estimates plus off-diagonal pairwise-sum estimates give the bundled finite slice target. The diagonal pair directions are supplied by rescaling the pure estimates.

theorem AleksandrovDifferentiability.directionalSliceQuotientEstimateAt_of_pure_offDiagonal {E : Type u_1} [NormedAddCommGroup E] [InnerProductSpace ℝ E] {ι : Type u_2} {D : Finset ι} {v : ι → E} {u : E → ℝ} {x : E} (hpure : ∀ ⦃i : ι⦄, i ∈ D → RealScalarQuadraticQuotientEstimateAt (lineRestriction u x (v i)) 0) (hpair : ∀ ⦃i : ι⦄, i ∈ D → ∀ ⦃j : ι⦄, j ∈ D → i ≠ j → RealScalarQuadraticQuotientEstimateAt (lineRestriction u x (v i + v j)) 0) :

Quotient-estimate version of directionalSliceEstimateAt_of_pure_offDiagonal.

The symmetric compatible finite slice-estimate set is contained in the compatible finite slice-estimate set.

The compatible finite slice-estimate set is contained in the older existential finite slice-estimate set.

The mixed-directional estimate set is contained in the finite directional slice quotient-estimate set.

The compatible finite slice-estimate set is contained in the compatible finite quotient-slice estimate set.

The symmetric compatible finite slice-estimate set is contained in the symmetric compatible finite quotient-slice estimate set.

The compatible finite quotient-slice estimate set is contained in the older existential finite quotient-slice estimate set.

The compatible finite slice-estimate set is contained in the older existential finite quotient-slice estimate set.

The mixed-directional quotient-estimate set is contained in the finite directional slice-estimate set.

The mixed-directional quotient-estimate set is contained in the finite directional slice quotient-estimate set.

The mixed-directional quotient-estimate set is contained in the compatible finite quotient-slice estimate set.

The mixed-directional quotient-estimate set is contained in the symmetric-compatible finite quotient-slice estimate set.

The compatible finite quotient-slice estimate set is contained in the symmetric compatible finite quotient-slice estimate set.

The symmetric compatible finite quotient-slice estimate set is contained in the compatible finite quotient-slice estimate set.

The polarized mixed-directional estimate set is contained in the finite directional slice-estimate set.

The polarized mixed-directional estimate set is contained in the finite directional slice quotient-estimate set.

The polarized mixed-directional estimate set is contained in the compatible finite slice-estimate set.

The polarized mixed-directional quotient estimate set is contained in the finite directional slice-estimate set.

The polarized mixed-directional quotient estimate set is contained in the finite directional slice quotient-estimate set.

The polarized mixed-directional quotient-estimate set is contained in the compatible finite quotient-slice estimate set.