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MIPRE.Background.LIDT.Co.SelfImprovement.Theorems.Results.BoundednessTransport.BoundednessGap

Boundedness transport boundedness-gap estimates #

The helper boundedness-gap decomposition, its data-processing transport, and the final projective-residual boundedness constructors of the self-improvement proof: the counterpart of the vendored SelfImprovement/Theorems/Results/BoundednessTransport/BoundednessGap.lean (under MIPRE/Background/LIDT/MIPStarRE/LDT/) in the port of planning/c6b-plan.md (milestone M10, section "Port conventions").

Contents #

The translation is that of BoundednessTransport/PointConsistency.lean: a strategy is a SymStrat params 𝔓 K, opTensor A B is strategy.state.opTensor A B, leftTensor (ι₂ := ι) X and rightTensor (ι₁ := ι) X are strategy.state.L X and strategy.state.R X, ev strategy.state is strategy.state.ev, the lifts F.liftLeft, F.liftRight are IdxSubMeas.liftLeft strategy.state F, IdxSubMeas.liftRight strategy.state F (and SubMeas.liftLeft S A for a single submeasurement), helperUpperOperator params Z is helperUpperOperator strategy.state params Z, and Error is ℝ.

The vendored swap strategy.permInvState.swap_ev Hhat.total is the keystone's strategy.state.ev_L_eq_ev_R Hhat.total; the vendored sddRel_liftRight_of_liftLeft_permInv strategy.permInvState … is M8's MakingMeasurementsProjective.sddRel_liftRight_of_liftLeft_permInv strategy.state …; the vendored strategy.isNormalized argument of Preliminaries.easyApproxFromApproxDelta is dropped, the ported lemma taking none. In final_fields_bounded the vendored (ψ : QuantumState (ι × ι)) is the model (S : SymModel 𝔓 K), an explicit first argument, and Matrix.PosSemidef.one.nonneg is zero_le_one. The hypotheses hslack : ∀ h, T_h A_h = T_h Z are SDP complementary slackness passed through, of unchanged shape. No statement of the vendored file carries a swap, density or normalization hypothesis, so no statement changed beyond the translation; the file sets no option, the vendored file-wide respectTransparency false not being needed.

The classical threshold lemmas helper_boundedness_error_le_selfImprovementHelperError (vendored Thresholds/Helper.lean) and final_fields_projective_residual_error_le_selfImprovementError (vendored Thresholds/Final.lean) are imported; the imports mirror the vendored one.

Not ported #

Every declaration of the vendored file has a counterpart here.

References #

In LionSR/MIPStarRE at commit 507e8122, not in this repository:

theorem MIPRE.LIDT.Co.SelfImprovement.helper_boundedness_gap_eq_upper_gap_add_off_diagonal_avg {𝔓 : Type u_1} [CStarAlgebra 𝔓] [PartialOrder 𝔓] [StarOrderedRing 𝔓] {K : Type u_2} [NormedAddCommGroup K] [InnerProductSpace ℂ K] [CompleteSpace K] (params : MIPStarRE.LDT.Parameters) [MIPStarRE.LDT.FieldModel params.q] (strategy : SymStrat params 𝔓 K) (H : SubMeas (MIPStarRE.LDT.Polynomial params) 𝔓) (Z : 𝔓) :
helperBoundednessGap params strategy H Z = strategy.state.ev (helperUpperOperator strategy.state params Z) - strategy.state.ev (strategy.state.R H.total) + MIPStarRE.LDT.avgOver (MIPStarRE.LDT.uniformDistribution (MIPStarRE.LDT.Point params)) fun (u : MIPStarRE.LDT.Point params) => ∑ h : MIPStarRE.LDT.Polynomial params, ∑ a ∈ Finset.univ.erase (h.toFun u), strategy.state.ev (strategy.state.opTensor ((strategy.pointMeasurement u).outcome a) (H.outcome h))

Algebraic decomposition of the helper boundedness gap.

The scalar gap ⟨Z ⊗ I - helperAgreementAverageOperator⟩ is the sum of ⟨Z ⊗ I⟩ - ⟨I ⊗ H.total⟩ and the off-diagonal average produced by helper_boundedness_slack_average_ev_eq_off_diagonal_avg.

theorem MIPRE.LIDT.Co.SelfImprovement.helper_boundedness_gap_le_selfImprovementHelperError {𝔓 : Type u_1} [CStarAlgebra 𝔓] [PartialOrder 𝔓] [StarOrderedRing 𝔓] {K : Type u_2} [NormedAddCommGroup K] [InnerProductSpace ℂ K] [CompleteSpace K] (params : MIPStarRE.LDT.Parameters) [MIPStarRE.LDT.FieldModel params.q] (strategy : SymStrat params 𝔓 K) (eps delta : ℝ) (heps : 0 ≤ eps) (hdelta : 0 ≤ delta) {Hhat : SubMeas (MIPStarRE.LDT.Polynomial params) 𝔓} {Z : 𝔓} (hZ_vs_H : strategy.state.ev (helperUpperOperator strategy.state params Z) - strategy.state.ev (strategy.state.R Hhat.total) ≤ 3 * √delta) (hoffdiag : (MIPStarRE.LDT.avgOver (MIPStarRE.LDT.uniformDistribution (MIPStarRE.LDT.Point params)) fun (u : MIPStarRE.LDT.Point params) => ∑ h : MIPStarRE.LDT.Polynomial params, ∑ a ∈ Finset.univ.erase (h.toFun u), strategy.state.ev (strategy.state.opTensor ((strategy.pointMeasurement u).outcome a) (Hhat.outcome h))) ≤ 4 * √(MIPStarRE.LDT.SelfImprovement.selfImprovementVarianceError params eps delta)) :

Helper-stage boundedness from the scalar comparison and the off-diagonal estimate.

The comparison ⟨Z ⊗ I⟩ - ⟨I ⊗ Hhat.total⟩ ≤ 3 √δ and the off-diagonal estimate ≤ 4 √ζ_variance give the helper threshold, by helper_boundedness_error_le_selfImprovementHelperError.

Helper-stage boundedness from the scalar comparison and the point-consistency add-in-u transfer: the off-diagonal estimate of pointConsistencyAddInU_off_diagonal_avg_le_of_transfer composed with helper_boundedness_gap_le_selfImprovementHelperError.

theorem MIPRE.LIDT.Co.SelfImprovement.helper_upper_gap_rightTensor_le_three_sqrt_delta_of_helper_outputs {𝔓 : Type u_1} [CStarAlgebra 𝔓] [PartialOrder 𝔓] [StarOrderedRing 𝔓] {K : Type u_2} [NormedAddCommGroup K] [InnerProductSpace ℂ K] [CompleteSpace K] (params : MIPStarRE.LDT.Parameters) [MIPStarRE.LDT.FieldModel params.q] (strategy : SymStrat params 𝔓 K) (eps delta : ℝ) {T : Measurement (MIPStarRE.LDT.Polynomial params) 𝔓} {Hhat : SubMeas (MIPStarRE.LDT.Polynomial params) 𝔓} {Z : 𝔓} (hhelper : SelfImprovementHelperConclusion params strategy T Hhat Z eps delta) (hssc : strategy.state.BipartiteSSCRel (MIPStarRE.LDT.uniformDistribution (MIPStarRE.LDT.Point params)) strategy.pointMeasurement.toIdxSubMeas delta) (hslack : ∀ (h : MIPStarRE.LDT.Polynomial params), T.outcome h * averagedPointOperator params strategy h = T.outcome h * Z) :
strategy.state.ev (helperUpperOperator strategy.state params Z) - strategy.state.ev (strategy.state.R Hhat.total) ≤ 3 * √delta

Convert the helper-completeness Hhat-versus-Z comparison to the right-placed total comparison used in the boundedness gap.

The helper-completeness paragraph proves ⟨Z ⊗ I⟩ - 3√δ ≤ subMeasMass (Hhat.liftLeft S); the swap symmetry of the model, S.ev_L_eq_ev_R, turns the left-placed total into the right-placed one.

Helper-stage boundedness from the helper comparison and the point-consistency add-in-u transfer.

Complementary slackness hslack and the off-diagonal transfer htransfer remain explicit hypotheses, as in the vendored statement.

Transport the helper boundedness gap through the data-processing approximation between Hhat and H: replacing the helper polynomial family in the point-agreement average by the projective family costs at most √ε (Proposition easy-approx-from-approx-delta).

theorem MIPRE.LIDT.Co.SelfImprovement.projective_boundedness_gap_le_helper_boundedness_gap {𝔓 : Type u_1} [CStarAlgebra 𝔓] [PartialOrder 𝔓] [StarOrderedRing 𝔓] {K : Type u_2} [NormedAddCommGroup K] [InnerProductSpace ℂ K] [CompleteSpace K] (params : MIPStarRE.LDT.Parameters) [MIPStarRE.LDT.FieldModel params.q] (strategy : SymStrat params 𝔓 K) (H : ProjSubMeas (MIPStarRE.LDT.Polynomial params) 𝔓) (Z : 𝔓) (hdual : ∀ (h : MIPStarRE.LDT.Polynomial params), 0 ≤ sdpDualSlackOperator params strategy Z h) :
projectiveBoundednessGap params strategy H Z ≤ helperBoundednessGap params strategy H.toSubMeas Z

Compare the final projective residual with the helper boundedness gap for the same projective family.

This is the SDP dual-slack step of the projective boundedness paragraph: Z ⊗ H_h dominates (E_u A^u_{h(u)}) ⊗ H_h for each polynomial h, and summing turns Z ⊗ (I - H) into the helper-stage defect Z ⊗ I - E_u Σ_a A^u_a ⊗ H_[h(u)=a].

Natural-error projective-residual construction.

Given the helper-stage boundedness estimate for Hhat, the dual-slack comparison and the data-processing transport give the final projective residual at the natural error selfImprovementHelperError + √selfImprovementDataProcessingError.

Paper source: references/ldt-paper/self_improvement.tex lines 742--755.

Literal-threshold projective-residual construction: the natural bound followed by a separately named numerical absorption habsorb.

Paper source: references/ldt-paper/self_improvement.tex lines 742--755.

theorem MIPRE.LIDT.Co.SelfImprovement.final_fields_projective_residual_bound_of_small_errors {𝔓 : Type u_1} [CStarAlgebra 𝔓] [PartialOrder 𝔓] [StarOrderedRing 𝔓] {K : Type u_2} [NormedAddCommGroup K] [InnerProductSpace ℂ K] [CompleteSpace K] (params : MIPStarRE.LDT.Parameters) [MIPStarRE.LDT.FieldModel params.q] (strategy : SymStrat params 𝔓 K) (eps delta : ℝ) (heps : 0 ≤ eps) (heps_le_one : eps ≤ 1) (hdelta : 0 ≤ delta) (hdelta_le_one : delta ≤ 1) (hd_le_q : ↑params.d ≤ ↑params.q) {T : Measurement (MIPStarRE.LDT.Polynomial params) 𝔓} {Hhat : SubMeas (MIPStarRE.LDT.Polynomial params) 𝔓} {H : ProjSubMeas (MIPStarRE.LDT.Polynomial params) 𝔓} {Z : 𝔓} (hhelper : SelfImprovementHelperConclusion params strategy T Hhat Z eps delta) (hhelperBounded : helperBoundednessGap params strategy Hhat Z ≤ MIPStarRE.LDT.SelfImprovement.selfImprovementHelperError params eps delta) (hdata : strategy.state.SDDRel (MIPStarRE.LDT.uniformDistribution (MIPStarRE.LDT.Point params)) (IdxSubMeas.liftLeft strategy.state (polynomialEvaluationFamily params Hhat)) (IdxSubMeas.liftLeft strategy.state (polynomialEvaluationFamily params H.toSubMeas)) (MIPStarRE.LDT.SelfImprovement.selfImprovementDataProcessingError params eps delta)) :

Literal-threshold projective-residual construction under the standard unit-interval smallness hypotheses, the absorption being final_fields_projective_residual_error_le_selfImprovementError.

Paper source: references/ldt-paper/self_improvement.tex lines 742--755.

theorem MIPRE.LIDT.Co.SelfImprovement.final_fields_projective_residual_bound_of_helper_outputs {𝔓 : Type u_1} [CStarAlgebra 𝔓] [PartialOrder 𝔓] [StarOrderedRing 𝔓] {K : Type u_2} [NormedAddCommGroup K] [InnerProductSpace ℂ K] [CompleteSpace K] (params : MIPStarRE.LDT.Parameters) [MIPStarRE.LDT.FieldModel params.q] (strategy : SymStrat params 𝔓 K) (eps delta : ℝ) (heps : 0 ≤ eps) (heps_le_one : eps ≤ 1) (hdelta : 0 ≤ delta) (hdelta_le_one : delta ≤ 1) (hd_le_q : ↑params.d ≤ ↑params.q) {T : Measurement (MIPStarRE.LDT.Polynomial params) 𝔓} {Hhat : SubMeas (MIPStarRE.LDT.Polynomial params) 𝔓} {H : ProjSubMeas (MIPStarRE.LDT.Polynomial params) 𝔓} {Z : 𝔓} (hhelper : SelfImprovementHelperConclusion params strategy T Hhat Z eps delta) (hssc : strategy.state.BipartiteSSCRel (MIPStarRE.LDT.uniformDistribution (MIPStarRE.LDT.Point params)) strategy.pointMeasurement.toIdxSubMeas delta) (hslack : ∀ (h : MIPStarRE.LDT.Polynomial params), T.outcome h * averagedPointOperator params strategy h = T.outcome h * Z) (htransfer : |addInULeftQuantity params strategy strategy.pointMeasurement.toIdxSubMeas Hhat (MIPStarRE.LDT.SelfImprovement.pointConsistencyAddInUSelection params) - addInURightQuantity params strategy strategy.pointMeasurement.toIdxSubMeas T.toSubMeas (MIPStarRE.LDT.SelfImprovement.pointConsistencyAddInUSelection params)| ≤ MIPStarRE.LDT.SelfImprovement.addInUError params eps delta) (hdata : strategy.state.SDDRel (MIPStarRE.LDT.uniformDistribution (MIPStarRE.LDT.Point params)) (IdxSubMeas.liftLeft strategy.state (polynomialEvaluationFamily params Hhat)) (IdxSubMeas.liftLeft strategy.state (polynomialEvaluationFamily params H.toSubMeas)) (MIPStarRE.LDT.SelfImprovement.selfImprovementDataProcessingError params eps delta)) :

Final projective-residual construction from helper outputs and the point-consistency add-in-u transfer: the helper-stage bound of helper_boundedness_gap_le_selfImprovementHelperError_of_helper_outputs, then final_fields_projective_residual_bound_of_small_errors.

Paper source: references/ldt-paper/self_improvement.tex lines 742--755.

theorem MIPRE.LIDT.Co.SelfImprovement.final_fields_bounded {𝔓 : Type u_1} [CStarAlgebra 𝔓] [PartialOrder 𝔓] [StarOrderedRing 𝔓] {K : Type u_2} [NormedAddCommGroup K] [InnerProductSpace ℂ K] [CompleteSpace K] {α : Type u_3} [Fintype α] (S : SymModel 𝔓 K) (A : SubMeas α 𝔓) {Z : 𝔓} (hOne : 1 ≤ Z) {ε : ℝ} (hε : 0 ≤ ε) :

Final-fields constructor for the BoundedByOperator conclusion.

If 1 ≤ Z, the left-placed mass of any submeasurement is dominated by Z ⊗ I: A.total ≤ 1 ≤ Z lifts by monotonicity of S.L and of ev, so bndError (A.liftLeft S) (Z ⊗ I) = 0 and the boundedness statement holds at any nonnegative tolerance.