Estimation.PLR
Partially linear regression DML: Robinson partialling-out scores, nuisance bundles, mean-zero and remainder facts, Jacobian consistency, and one-step plus feasible asymptotic normality.
Nuisance 2 core · 8 supporting This file packages the two partially-linear-model nuisance functions — the outcome regression lFn and the treatment regression mFn — together with their measurability witnesses into a single type PLRNuisance, and equips ★ ext
Bundled nuisance space for the partially linear model
This file packages the two partially-linear-model nuisance functions — the
outcome regression lFn and the treatment regression mFn — together with
their measurability witnesses into a single type PLRNuisance, and equips it
with componentwise real-vector-space structure. This bundled nuisance space is
the nuisance space used by the partially linear double-machine-learning moment
instance.
A partially linear nuisance bundles an outcome regression and a treatment regression on the covariates, requiring each to be measurable.
Definition (Lean source)
Two nuisance pairs η and η' are equal whenever their outcome-regression components agree at every covariate value and their treatment-regression components agree at every covariate value, so the two pairs are equal.
Formal statement
Proof (Lean source)
8 supporting declarations (lemmas, instances)
-
instZeroinstance — For every covariate space equipped with a $\sigma$-algebra, the zero operation on partially linear nuisance pairs assigns the pair whose outcome and treatment regressions are both identically zero.parametersγ :sharedType u_1instancegiven byzero := ⟨fun _ => 0, fun _ => 0, measurable_const, measurable_const⟩ -
instAddinstance — For every covariate space equipped with a $\sigma$-algebra, the addition operation on partially linear nuisance pairs assigns to each pair of nuisance pairs the pair obtained by adding their outcome regressions and their treatment regressions pointwise.parametersγ :sharedType u_1instancegiven byadd η η' := ⟨fun x=> η.lFn x+ η'.lFn x, fun x => η.mFn x+ η'.mFn x, η.lMeas.add η'.lMeas, η.mMeas.add η'.mMeas⟩ -
instNeginstance — For every covariate space equipped with a $\sigma$-algebra, the negation operation on partially linear nuisance pairs assigns to each nuisance pair the pair obtained by negating both regressions pointwise.parametersγ :sharedType u_1instancegiven byneg η := ⟨fun x => -η.lFn x, fun x => -η.mFn x, η.lMeas.neg, η.mMeas.neg⟩ -
instSubinstance — For every covariate space equipped with a $\sigma$-algebra, the subtraction operation on partially linear nuisance pairs assigns to each ordered pair of nuisance pairs the pair obtained by subtracting their outcome regressions and their treatment regressions pointwise.parametersγ :sharedType u_1instancegiven bysub η η' := ⟨fun x=> η.lFn x- η'.lFn x, fun x => η.mFn x- η'.mFn x, η.lMeas.sub η'.lMeas, η.mMeas.sub η'.mMeas⟩ -
instSMulRealinstance — For every covariate space equipped with a $\sigma$-algebra, the real-scalar multiplication operation on partially linear nuisance pairs assigns to every real scalar and nuisance pair the pair obtained by multiplying both regressions pointwise by that scalar.parametersγ :sharedType u_1instancegiven bysmul t η := ⟨fun x=> t * η.lFn x, fun x => t * η.mFn x, measurable_const.mul η.lMeas, measurable_const.mul η.mMeas⟩ -
ext_ifftheorem∀ {γ : Type u_1} [inst : MeasurableSpace γ] {η η' : PLRNuisance γ}, η = η' ↔ (∀ (x : γ), η.lFn x = η'.lFn x) ∧ ∀ (x : γ), η.mFn x = η'.mFn xProof (Lean source)
@[ext] -
instAddCommGroupinstance — For every covariate space equipped with a $\sigma$-algebra, the additive commutative group structure on partially linear nuisance pairs supplies the zero pair, componentwise addition, componentwise negation, componentwise subtraction, repeated addition by natural numbers, repeated addition and negation by integers, the zero-multiple law, the successor-multiple law, the zero integer-multiple law, the positive successor integer-multiple law, the negative successor integer-multiple law, subtraction as addition of a negative, associativity of addition, the left zero law, the right zero law, cancellation of a pair with its negative, and commutativity of addition.parametersγ :sharedType u_1instancegiven byclause 1zero := 0clause 2add := (· + ·)clause 4sub := Sub.subclause 5nsmul := nsmulRecclause 6zsmul := zsmulRecclause 7nsmul_zero η := by rflclause 8nsmul_succ n η := by rflclause 9zsmul_zero' η := by rflclause 10zsmul_succ' n η := by rflclause 11zsmul_neg' n η := by rflclause 12sub_eq_add_neg η η' := by apply ext <;> intro x · exact sub_eq_add_neg (η.lFn x) (η'.lFn x) · exact sub_eq_add_neg (η.mFn x) (η'.mFn x)clause 13add_assoc η η' η'' := by apply ext <;> intro x · exact add_assoc (η.lFn x) (η'.lFn x) (η''.lFn x) · exact add_assoc (η.mFn x) (η'.mFn x) (η''.mFn x)clause 14zero_add η := by apply ext <;> intro x · exact zero_add (η.lFn x) · exact zero_add (η.mFn x)clause 15add_zero η := by apply ext <;> intro x · exact add_zero (η.lFn x) · exact add_zero (η.mFn x)clause 16neg_add_cancel η := by apply ext <;> intro x · exact neg_add_cancel (η.lFn x) · exact neg_add_cancel (η.mFn x)clause 17add_comm η η' := by apply ext <;> intro x · exact add_comm (η.lFn x) (η'.lFn x) · exact add_comm (η.mFn x) (η'.mFn x) -
instModuleRealinstance — For every covariate space equipped with a $\sigma$-algebra, the real vector-space structure on partially linear nuisance pairs supplies the scalar multiplication operation, the unit-scalar law, the successive-scalar law, the scalar-times-zero law, distributivity of scalar multiplication over addition of nuisance pairs, distributivity over addition of scalars, and the zero-scalar law.parametersγ :sharedType u_1instancegiven byclause 1smul := (· • ·)clause 2one_smul η := by apply ext <;> intro x · change (1 : ℝ) * η.lFn x= η.lFn x exact one_mul _ · change (1 : ℝ) * η.mFn x = η.mFn x exact one_mul _clause 3mul_smul t u η := by apply ext <;> intro x · change (t * u) * η.lFn x= t * (u * η.lFn x) ring · change (t * u) * η.mFn x = t * (u * η.mFn x) ringclause 4smul_zero t := by apply ext <;> intro x · change t * (0 : ℝ)= 0 exact mul_zero t · change t * (0 : ℝ) = 0 exact mul_zero tclause 5smul_add t η η' := by apply ext <;> intro x · change t * (η.lFn x + η'.lFn x)= t * η.lFn x+ t * η'.lFn x ring · change t * (η.mFn x + η'.mFn x) = t * η.mFn x+ t * η'.mFn x ringclause 6add_smul t u η := by apply ext <;> intro x · change (t + u) * η.lFn x= t * η.lFn x+ u * η.lFn x ring · change (t + u) * η.mFn x = t * η.mFn x+ u * η.mFn x ringclause 7zero_smul η := by apply ext <;> intro x · change (0 : ℝ) * η.lFn x= 0 exact zero_mul _ · change (0 : ℝ) * η.mFn x = 0 exact zero_mul _
Moment 5 core · 4 supporting This file provides the partialling-out moment functional for the partially linear model, its decomposition into the linear-in-parameter form, and the measurability of these maps in the data. ★ plrMoment_decomp
Partially linear orthogonal score
This file provides the partialling-out moment functional for the partially linear model, its decomposition into the linear-in-parameter form, and the measurability of these maps in the data. The score is linear in the structural slope, with coefficient minus the squared treatment residual and constant term given by the residualized outcome times the treatment residual.
For a measurable covariate space, a pair of outcome and treatment regression functions, and an observed covariate, treatment, and outcome triple, the partially linear treatment residual is the observed treatment minus its treatment-regression prediction.
Definition (Lean source)
For a measurable covariate space, a pair of outcome and treatment regression functions, an observed covariate, treatment, and outcome triple, and a real-valued structural slope, the Robinson partialling-out score is the product of the treatment residual and the outcome residual after subtracting that slope times the treatment residual.
Definition (Lean source)
For a measurable covariate space, a pair of outcome and treatment regression functions, and an observed covariate, treatment, and outcome triple, the coefficient of the partially linear score that is linear in the structural slope is minus the squared treatment residual.
Definition (Lean source)
For a measurable covariate space, a pair of outcome and treatment regression functions, and an observed covariate, treatment, and outcome triple, the constant term in the partially linear score is the product of the treatment residual and the outcome minus its outcome-regression prediction.
Definition (Lean source)
Robinson score decomposition. The partialling-out score decomposes into its linear coefficient in θ times the target parameter θ plus a constant term.
Formal statement
Proof (Lean source)
4 supporting declarations (lemmas, instances)
-
measurable_plrResiduallemma — The treatment residual is measurable as a function of the observed data.Proof (Lean source)
@[fun_prop] lemma measurable_plrResidual (η : PLRNuisance γ) : Measurable (fun z : γ × ℝ × ℝ => plrResidual η z) := (measurable_fst.comp measurable_snd).sub (η.mMeas.comp measurable_fst) -
measurable_plrMomentFunctionallemma — The Robinson partialling-out score is measurable in the observed data.hypothesesconclusionMeasurable (fun z : γ × ℝ × ℝ => plrMomentFunctional η z θ)Proof (Lean source)
@[fun_prop] lemma measurable_plrMomentFunctional (η : PLRNuisance γ) (θ : ℝ) : Measurable (fun z : γ × ℝ × ℝ => plrMomentFunctional η z θ) := by have hv := measurable_plrResidual η have hy : Measurable (fun z : γ × ℝ × ℝ => z.2.2) := by fun_prop exact (((hy.sub (η.lMeas.comp measurable_fst)).sub (hv.const_mul θ)).mul hv) -
measurable_plrMomentAlemma — The linear-score coefficient is measurable in the observed data.Proof (Lean source)
@[fun_prop] lemma measurable_plrMomentA (η : PLRNuisance γ) : Measurable (fun z : γ × ℝ × ℝ => plrMomentA η z) := by have hv := measurable_plrResidual η exact (hv.pow_const 2).neg -
measurable_plrMomentBlemma — The linear-score constant term is measurable in the observed data.Proof (Lean source)
@[fun_prop] lemma measurable_plrMomentB (η : PLRNuisance γ) : Measurable (fun z : γ × ℝ × ℝ => plrMomentB η z) := by have hv := measurable_plrResidual η have hy : Measurable (fun z : γ × ℝ × ℝ => z.2.2) := by fun_prop exact (hy.sub (η.lMeas.comp measurable_fst)).mul hv
Setup 9 core · 4 supporting This file provides the value-space estimation system carrying the regression representatives, the joint observed-data law, and the GeneralMoment instance of the abstract DML framework. ★ plrMomentFunctional_factualZ
Partially linear DML estimation system
This file provides the value-space estimation system carrying the regression
representatives, the joint observed-data law, and the GeneralMoment instance of
the abstract DML framework. The main declarations are PLRSystem,
PLRSystem.factualZ, PLRSystem.P_Z, PLRSystem.P_X, PLRSystem.η₀,
PLRSystem.θ₀, PLRSystem.residSecondMoment, PLRSystem.plrGeneralMoment, and
the change-of-variables helper PLRSystem.integral_P_Z. The resulting partially
linear moment has a DGP-dependent Jacobian equal to minus the residual treatment
variance; sibling files prove the mean-zero, finite-variance, score-L², and
doubly-robust remainder facts used for structural-slope DML normality.
A partially linear estimation system extends a partially linear causal model with value-space regression representatives — an outcome-regression representative and a treatment-regression representative on the covariates — subject to: each representative is measurable; the outcome representative agrees almost surely with the conditional mean of the outcome given the covariates and the treatment representative agrees almost surely with the conditional mean of the treatment given the covariates; and the treatment retains nonzero variation after partialling out the covariate, which is what makes the partialling-out Jacobian invertible.
Definition (Lean source)
For a partially linear potential-outcomes system with a finite population measure and a measurable covariate space and a partially linear estimation system built on it, the observed-data map assigns every population unit its covariate, factual treatment, and factual outcome, in that order.
For a partially linear potential-outcomes system with a finite population measure and a measurable covariate space and a partially linear estimation system built on it, the joint observed-data measure is the population measure transported through the map that records each unit's covariate, factual treatment, and factual outcome.
For a partially linear potential-outcomes system with a finite population measure and a measurable covariate space and a partially linear estimation system built on it, the covariate marginal measure is the population measure transported through the factual covariate map.
For a partially linear potential-outcomes system with a finite population measure and a measurable covariate space and a partially linear estimation system built on it, the true nuisance pair consists of that system's value-space outcome regression and treatment regression.
Definition (Lean source)
For a partially linear potential-outcomes system with a finite population measure and a measurable covariate space and a partially linear estimation system built on it, the target parameter is the structural slope of its partially linear model.
For a partially linear potential-outcomes system with a finite population measure and a measurable covariate space and a partially linear estimation system built on it, the residual treatment second moment is the population integral of the squared difference between factual treatment and its value-space treatment regression evaluated at the factual covariate.
For a partially linear potential-outcomes system with a finite population measure and a measurable covariate space and a partially linear estimation system built on it, the partially linear general moment system is the abstract moment system with the Robinson partialling-out score, the system's true regression pair and structural slope, and a Jacobian equal to the negative residual treatment second moment.
Definition (Lean source)
Robinson score at the true nuisance, pulled back to the population space. For the observed data generated from a population outcome ω, the Robinson partialling-out score evaluated at the true nuisance pair, true data, and true parameter equals the true residualized outcome times the true treatment residual.
Formal statement
Proof (Lean source)
4 supporting declarations (lemmas, instances)
-
measurable_factualZlemma — The observed-data map is measurable.hypothesesconclusionMeasurable S.factualZProof (Lean source)
@[fun_prop] lemma measurable_factualZ : Measurable S.factualZ := S.measurable_factualX.prodMk (S.measurable_factualD.prodMk S.measurable_factualY) -
P_Z_eqlemma — The joint observed-data law is the image of the population measure under the map recording the observed covariate, treatment, and outcome.hypothesesconclusionS.P_Z = P.μ.map S.factualZProof (Lean source)
@[causal_defs_simps] lemma P_Z_eq : S.P_Z = P.μ.map S.factualZ := rfl -
P_X_eqlemma — The covariate marginal is the image of the population measure under the observed covariate map.hypothesesconclusionS.P_X = P.μ.map S.factualXProof (Lean source)
@[causal_defs_simps] lemma P_X_eq : S.P_X = P.μ.map S.factualX := rfl -
integral_P_Zlemma — Integrating a measurable function under the joint observed-data law equals integrating its pullback under the population measure.hypothesesγ :sharedType u_1f :γ × ℝ × ℝ → ℝhf :conclusion∫ z, f z ∂S.P_Z = ∫ ω, f (S.factualZ ω) ∂P.μProof (Lean source)
lemma integral_P_Z {f : γ × ℝ × ℝ → ℝ} (hf : Measurable f) : ∫ z, f z ∂S.P_Z = ∫ ω, f (S.factualZ ω) ∂P.μ := by rw [P_Z, MeasureTheory.integral_map S.measurable_factualZ.aemeasurable hf.aestronglyMeasurable]
DML 2 core · 0 supporting This file delivers the asymptotic linearity and √n-asymptotic normality of the one-step double-machine-learning estimator of the structural slope in the partially linear model, by composing the abstract Chernozhukov-form ★ plr_dml_isAsymLinear★ plr_dml_tendstoNormal
Headline partially linear DML theorems
This file delivers the asymptotic linearity and √n-asymptotic normality of the one-step double-machine-learning estimator of the structural slope in the partially linear model, by composing the abstract Chernozhukov-form engine with the three model-specific analytic facts (mean-zero, finite-variance, doubly-robust remainder) and the generic asymptotic-linearity ⇒ normality bridge.
Headline partially linear DML asymptotic-linearity theorem. Fix a partially linear estimation system, an i.i.d. sample of covariate-treatment-outcome triples, and a sample split whose evaluation-fold share converges to a fixed positive limit. If the model's integrability and square-integrability conditions hold — the structural error, its product with the treatment residual, the baseline-covariate term, and the treatment are integrable, the true treatment residual is square-integrable, and the true score has finite second moment; for the estimated nuisance sequence η_hat, at every fold and draw the outcome- and treatment-regression errors are square-integrable in the covariate law, with the resulting cross terms against the structural error and the treatment residual integrable; the estimated score is jointly measurable, fold-A measurable, and integrable/square-integrable at every fold; the L²(P_Z) distance between the estimated and true score is ; and the product of the two nuisance-error seminorms is ; then the one-step double-machine-learning estimator of the structural slope is asymptotically linear at the true slope, with influence function — the inverse-Jacobian-scaled Robinson partialling-out score at the truth.
Formal statement
Proof (Lean source)
Headline partially linear DML asymptotic-normality theorem. Fix a partially linear estimation system, an i.i.d. sample of covariate-treatment-outcome triples, and a sample split whose evaluation-fold share converges to a fixed positive limit. Suppose the structural error, its product with the treatment residual, the baseline-covariate term, and the treatment are integrable, the true treatment residual is square-integrable, and the true score has finite second moment; for the estimated nuisance sequence η_hat, the outcome- and treatment-regression errors are square-integrable in the covariate law at every fold and draw, with the resulting cross terms against the structural error and the treatment residual integrable; the estimated score is jointly measurable and measurable as a function of the nuisance-training fold alone and jointly with the observation, and integrable and square-integrable at every fold and draw; the estimated score converges to the true score in L²(P_Z) at rate , and the product of the two nuisance-error seminorms is ; and the influence function, the rescaled estimator at each n, and the normalized influence sum at each n are all measurable. Then the rescaled double-machine-learning estimator of the structural slope, recentered at the true slope and scaled by the square root of the fold-B sample size, converges in distribution to a centered Gaussian whose variance is the second moment of the inverse-Jacobian-scaled partialling-out score at the true regressions.
Formal statement
Proof (Lean source)
Feasible 2 core · 0 supporting This file treats the one-dimensional partially linear regression model, so the orthogonal score is affine in a single scalar treatment-effect parameter. ★ plr_dml_feasible_tendstoNormal
Feasible partially linear DML
This file treats the one-dimensional partially linear regression model, so the
orthogonal score is affine in a single scalar treatment-effect parameter. It
defines the solved Robinson ratio estimator plrFeasibleEstimator, whose
numerator is the empirical covariance of residualized outcome and treatment and
whose denominator is the empirical treatment residual variance. The theorem
plr_dml_feasible_tendstoNormal reduces its √|B|-asymptotic normality to the
one-step normality theorem plr_dml_tendstoNormal by the standard
asymptotic-equivalence argument.
For a partially linear potential-outcomes system with a finite population measure and a measurable covariate space, a partially linear estimation system built on it, an independent and identically distributed sample from its joint observed-data law, a one-shot evaluation-fold split of that sample, a sequence of estimated outcome-and-treatment regression pairs, and a sample-size index, the feasible partially linear double-machine-learning estimator maps each population state to the ratio of the evaluation-fold sum of residualized-outcome times residualized-treatment to the evaluation-fold sum of squared residualized-treatment.
Definition (Lean source)
Feasible partially linear DML asymptotic-normality theorem. Fix a partially linear estimation system, an i.i.d. sample of covariate-treatment-outcome triples, and a sample split whose evaluation-fold share converges to a fixed positive limit. Suppose the structural error, its product with the treatment residual, the baseline-covariate term, and the treatment are integrable, the true treatment residual is square-integrable, and the true score has finite second moment; for the estimated nuisance sequence η_hat, the outcome- and treatment-regression errors are square-integrable in the covariate law at every fold and draw, with the resulting cross terms against the structural error and the treatment residual integrable; the estimated score is jointly measurable and measurable as a function of the nuisance-training fold alone and jointly with the observation, and integrable and square-integrable at every fold and draw; the estimated score converges to the true score in L²(P_Z) at rate , and the product of the two nuisance-error seminorms is ; and the influence function, the one-step rescaled estimator at each n, and the normalized influence sum at each n are all measurable. Suppose in addition the empirical partialling-out Jacobian over fold B converges in probability to its population value J₀, and the rescaled feasible estimator is measurable at each n. Then the rescaled feasible estimator — the solved Robinson partialling-out estimator, recentered at the true slope and scaled by the square root of the fold-B sample size — converges in distribution to the same centered Gaussian as the one-step estimator: a normal law whose variance is the population second moment of the inverse-Jacobian-scaled partialling-out score at the true regressions.
Formal statement
Proof (Lean source)
JacobianConsistency 1 core · 3 supporting This file proves that the empirical Jacobian of the partially linear partialling-out score, averaged over the estimation fold, converges in probability to its population value. ★ plr_jacobian_consistency
Fold-B partialling-out Jacobian consistency
This file proves that the empirical Jacobian of the partially linear partialling-out score, averaged over the estimation fold, converges in probability to its population value. It supplies the Jacobian-consistency condition needed by the feasible partially linear double-machine-learning asymptotic-normality result.
Fold-B Jacobian consistency. Assume the treatment is integrable; the true partialling-out moment at the truth is square-integrable under the observed-data law, and the squared true treatment residual is integrable; that for the estimated nuisance sequence η_hat, at every fold and draw, the treatment-regression error is square-integrable in the covariate law, both marginally and against the true treatment residual; that the treatment-regression error converges to zero in L²(P_X) at rate ; and that the partialling-out-moment increment mₐ(η̂,·) − mₐ(η₀,·) is jointly measurable, fold-A measurable, square-integrable under the observed-data law, and converges to zero in L²(P_Z) at rate . Then the empirical partialling-out Jacobian at the estimated nuisance, averaged over the estimation fold, converges in probability to its population value :
Formal statement
Proof (Lean source)
3 supporting declarations (lemmas, instances)
-
integral_plrMomentA_η₀_eq_J₀lemma — The population integral of the partialling-out moment at the truth equals the Jacobian: ∫ mₐ(η₀, ·) dP_Z = J₀ = −E[(D − m_val(X))²].hypothesesconclusion∫ z, plrMomentA S.η₀ z ∂S.P_Z = S.plrGeneralMoment.J₀Proof (Lean source)
lemma integral_plrMomentA_η₀_eq_J₀ (S : PLRSystem P γ) : ∫ z, plrMomentA S.η₀ z ∂S.P_Z = S.plrGeneralMoment.J₀ := by rw [S.integral_P_Z (measurable_plrMomentA S.η₀)] change ∫ ω, plrMomentA S.η₀ (S.factualZ ω) ∂P.μ = -S.residSecondMoment rw [residSecondMoment, ← integral_neg] apply integral_congr_ae filter_upwards with ω simp only [plrMomentA, plrResidual, η₀, factualZ] -
instIsProbabilityMeasureP_Zinstance — For a potential-outcome system equipped with a finite probability measure, a measurable covariate space, and a partially linear regression system based on them, the system's joint observed-data law is a probability measure.parametersinstancegiven byMeasure.isProbabilityMeasure_map S.measurable_factualZ.aemeasurable -
integral_plrMomentA_diff_eqlemma — Bias of the empirical-Jacobian increment. The population integral of the increment Δa := mₐ(η̂, ·) − mₐ(η₀, ·) is minus the squared L²(P_X) magnitude of the treatment-regression error Δm := m_val − m̂:hypothesesγ :sharedType u_1S :PLRSystem P γη :hD :Integrable S.factualD P.μhresid_sq :Integrable (fun ω => (S.factualD ω - S.mVal (S.factualX ω)) ^ 2) P.μhΔm_sq :Integrable (fun ω => (S.mVal (S.factualX ω) - η.mFn (S.factualX ω)) ^ 2) P.μhcross :Integrable (fun ω => (S.factualD ω - S.mVal (S.factualX ω)) * (S.mVal (S.factualX ω) - η.mFn (S.factualX ω))) P.μconclusion∫ z, (plrMomentA η z - plrMomentA S.η₀ z) ∂S.P_Z= -∫ ω, (S.mVal (S.factualX ω) - η.mFn (S.factualX ω)) ^ 2 ∂P.μProof (Lean source)
lemma integral_plrMomentA_diff_eq (S : PLRSystem P γ) (η : PLRNuisance γ) (hD : Integrable S.factualD P.μ) (hresid_sq : Integrable (fun ω => (S.factualD ω - S.mVal (S.factualX ω)) ^ 2) P.μ) (hΔm_sq : Integrable (fun ω => (S.mVal (S.factualX ω) - η.mFn (S.factualX ω)) ^ 2) P.μ) (hcross : Integrable (fun ω => (S.factualD ω - S.mVal (S.factualX ω)) * (S.mVal (S.factualX ω) - η.mFn (S.factualX ω))) P.μ) : ∫ z, (plrMomentA η z - plrMomentA S.η₀ z) ∂S.P_Z = -∫ ω, (S.mVal (S.factualX ω) - η.mFn (S.factualX ω)) ^ 2 ∂P.μ := by -- Change of variables to `μ`. have hmeas : Measurable (fun z => plrMomentA η z - plrMomentA S.η₀ z) := (measurable_plrMomentA η).sub (measurable_plrMomentA S.η₀) rw [S.integral_P_Z hmeas] -- Abbreviate the (pulled-back) residual and regression error. set V₀ : P.Ω → ℝ := fun ω => S.factualD ω - S.mVal (S.factualX ω) with hV₀_def set Δm : P.Ω → ℝ := fun ω => S.mVal (S.factualX ω) - η.mFn (S.factualX ω) with hΔm_def -- Pointwise expansion: `Δa ∘ Z = −2·V₀·Δm − Δm²`. have hpt : (fun ω => plrMomentA η (S.factualZ ω) - plrMomentA S.η₀ (S.factualZ ω)) = fun ω => (-2) * (V₀ ω * Δm ω) - Δm ω ^ 2 := by funext ω simp only [plrMomentA, plrResidual, η₀, factualZ, hV₀_def, hΔm_def] ring rw [hpt] -- Linearity of the integral over the two summands. have hsmul : Integrable (fun ω => (-2 : ℝ) * (V₀ ω * Δm ω)) P.μ := hcross.const_mul _ have hΔmsq' : Integrable (fun ω => Δm ω ^ 2) P.μ := hΔm_sq rw [integral_sub hsmul hΔmsq', integral_const_mul] -- The cross term `∫ V₀·Δm` vanishes by orthogonality of the residual. have hcross_zero : ∫ ω, V₀ ω * Δm ω ∂P.μ = 0 := by -- `V₀ =ᵐ resid` via `mVal_compat` (`m_val(X) =ᵐ mReg`, `resid = D − mReg`). have hV₀_ae : (fun ω => V₀ ω * Δm ω) =ᵐ[P.μ] fun ω => S.resid ω * Δm ω := by filter_upwards [S.mVal_compat] with ω hω simp only [hV₀_def] have hr : S.resid ω = S.factualD ω - S.mReg ω := rfl rw [hr, hω] rw [integral_congr_ae hV₀_ae] -- Orthogonality: `Δm = (m_val − m̂)(X)` is a covariate function, residual ⟂. have hh_meas : Measurable (fun x => S.mVal x - η.mFn x) := S.mVal_meas.sub η.mMeas have hresid_int : Integrable S.resid P.μ := by have : S.resid = fun ω => S.factualD ω - S.mReg ω := rfl rw [this] exact hD.sub MeasureTheory.integrable_condExp have hwg_int : Integrable (fun ω => S.resid ω * (S.mVal (S.factualX ω) - η.mFn (S.factualX ω))) P.μ := by have hae : (fun ω => S.resid ω * (S.mVal (S.factualX ω) - η.mFn (S.factualX ω))) =ᵐ[P.μ] fun ω => V₀ ω * Δm ω := by filter_upwards [S.mVal_compat] with ω hω simp only [hV₀_def, hΔm_def] have hr : S.resid ω = S.factualD ω - S.mReg ω := rfl rw [hr, hω] exact (hcross.congr hae.symm) exact S.integral_condExpZero_mul_comp_factualX hh_meas (S.condExp_resid_sigmaX hD) hresid_int hwg_int rw [hcross_zero] simp only [hΔm_def, mul_zero, zero_sub]
MeanZero 2 core · 0 supporting This file proves the two partially linear score facts consumed by the double machine-learning engine: plr_meanZero, the population mean-zero identity at the truth, and plr_finite_var, finite second moment of the true sco ★ plr_meanZero★ plr_finite_var
Mean-zero and finite variance for the partially linear score
This file proves the two partially linear score facts consumed by the double
machine-learning engine: plr_meanZero, the population mean-zero identity at the
truth, and plr_finite_var, finite second moment of the true score under the
observed-data law.
If the structural error is integrable, the product of the structural error and the true treatment residual is integrable, the baseline covariate function is integrable, and the treatment is integrable, then the Robinson partialling-out score, evaluated at the true outcome and treatment regressions and the true structural slope, has zero mean under the observed-data law.
Formal statement
Proof (Lean source)
If the squared Robinson partialling-out score — evaluated at the true outcome and treatment regressions and the true structural slope, pulled back to the population space — is integrable, then the squared score is integrable under the observed-data law , i.e. the score has finite variance at the truth.
Formal statement
Proof (Lean source)
RemainderBound 1 core · 1 supporting This file proves the doubly-robust bilinear bound on the population moment at an estimated nuisance, the analytic heart of the partially linear DML guarantee. ★ plr_remainder_bound
Doubly-robust remainder for the partially linear score
This file proves the doubly-robust bilinear bound on the population moment at an
estimated nuisance, the analytic heart of the partially linear DML guarantee.
The helper integral_condExpZero_mul_comp_factualX turns conditional
mean-zero-with-respect-to-σ(X) into orthogonality against covariate functions,
and plr_remainder_bound applies that orthogonality to bound the partially
linear population score by the product of outcome- and treatment-regression
L²(P_X) errors.
Doubly-robust bilinear remainder. Fix any candidate nuisance pair η of outcome and treatment regressions. Assume the treatment, the baseline covariate function, and the structural error are integrable; that the outcome- and treatment-regression errors of η and the true treatment residual are square-integrable; and that the resulting orthogonal cross terms and the true structural-error/treatment-residual product are all integrable. Then the population Robinson partialling-out score at η and the true structural slope is bounded in absolute value by times the product of the two L²(P_X) nuisance-error seminorms:
Formal statement
Proof (Lean source)
1 supporting declaration (lemmas, instances)
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integral_condExpZero_mul_comp_factualXlemma — Orthogonality of a σ(X)-conditionally-mean-zero variable w to any covariate function h(X): E[w·h(X)] = 0. Mirrors integral_U_resid, but the σ-algebra is σ(X) (so h(X) pulls out of the conditional expectation) instead of σ(X,D). Used to kill the three orthogonal cross terms U·Δm, Δℓ·V, V·Δm in the doubly-robust remainder.hypothesesγ :sharedType u_1w :P.Ω → ℝh :γ → ℝhh :hwz :P.μ[w | S.sigmaX] =ᵐ[P.μ] 0hw :Integrable w P.μhwg :Integrable (fun ω => w ω * h (S.factualX ω)) P.μconclusion∫ ω, w ω * h (S.factualX ω) ∂P.μ = 0Proof (Lean source)
lemma integral_condExpZero_mul_comp_factualX {w : P.Ω → ℝ} {h : γ → ℝ} (hh : Measurable h) (hwz : P.μ[w | S.sigmaX] =ᵐ[P.μ] 0) (hw : Integrable w P.μ) (hwg : Integrable (fun ω => w ω * h (S.factualX ω)) P.μ) : ∫ ω, w ω * h (S.factualX ω) ∂P.μ = 0 := by -- `h(X)` is `σ(X)`-strongly-measurable. have hg_sm : StronglyMeasurable[S.sigmaX] (fun ω => h (S.factualX ω)) := by change StronglyMeasurable[comap S.factualX inferInstance] (fun ω => h (S.factualX ω)) exact (hh.comp (comap_measurable S.factualX)).stronglyMeasurable -- `w·h(X) = h(X)·w` is integrable up to commutativity. have hgw_int : Integrable (fun ω => h (S.factualX ω) * w ω) P.μ := by simpa [mul_comm] using hwg -- Pull `h(X)` out of the conditional expectation, then `E[w|σX] = 0`. have hpull : P.μ[fun ω => h (S.factualX ω) * w ω | S.sigmaX] =ᵐ[P.μ] (fun ω => h (S.factualX ω)) * P.μ[w | S.sigmaX] := MeasureTheory.condExp_mul_of_stronglyMeasurable_left (μ := P.μ) (m := S.sigmaX) hg_sm hgw_int hw have hce_zero : P.μ[fun ω => h (S.factualX ω) * w ω | S.sigmaX] =ᵐ[P.μ] (fun _ => (0 : ℝ)) := by refine hpull.trans ?_ filter_upwards [hwz] with ω hω rw [Pi.mul_apply, hω, Pi.zero_apply, mul_zero] calc ∫ ω, w ω * h (S.factualX ω) ∂P.μ = ∫ ω, h (S.factualX ω) * w ω ∂P.μ := by simp_rw [mul_comm] _ = ∫ ω, P.μ[fun ω => h (S.factualX ω) * w ω | S.sigmaX] ω ∂P.μ := by rw [MeasureTheory.integral_condExp S.sigmaX_le] _ = ∫ _, (0 : ℝ) ∂P.μ := MeasureTheory.integral_congr_ae hce_zero _ = 0 := MeasureTheory.integral_zero _ _
ScoreL2 1 core · 0 supporting This file provides the standalone lemma plr_score_diff_isLittleOp_one, which discharges the score-difference o_p(1) hypothesis of the partially linear DML asymptotic-linearity theorem from boundedness of the truth residu ★ plr_score_diff_isLittleOp_one
Partially linear score L²(P_Z) o_p(1) continuity
This file provides the standalone lemma plr_score_diff_isLittleOp_one, which
discharges the score-difference o_p(1) hypothesis of the partially linear DML
asymptotic-linearity theorem from boundedness of the truth residuals, uniform
boundedness of the nuisance errors, and the two individual L²(P_X) nuisance
rates.
Score-difference L²(P_Z) o_p(1) for the partially linear model. Suppose three nonnegative bounding constants Ca, Cv, Cm satisfy: the residualized outcome is almost surely bounded by Ca under the observed-data law; the true treatment residual is almost surely bounded by Cv; and the treatment-regression estimation error of η_hat is uniformly bounded by Cm at every fold, draw, and covariate value. Suppose further that for the estimated nuisance sequence η_hat on the system S, the outcome- and treatment-regression estimation errors are square-integrable over the covariate law at every fold and draw, and that both regression errors converge to zero in L²(P_X) at rate . Then the L²(P_Z)-seminorm of the Robinson partialling-out score difference between the estimated and the true nuisance is itself .