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LeanPool.Superdiffusion.Algsuperdiff.Section3.Provider.Localization.ResponseTransport

ResponseTransport #

Ported from scottnarmstrong/Superdiffusion at 7f20476385d4af418f110303085ad0740c9eba46. Module imports, support namespace and local option directives adapted for Lean Pool.

Provider: the response transport of the localization breakdown #

Provider/Localization/Breakdown.lean produces, for the Section 3 carrier, the display e.mathcal.E.breakdown with its two legs breakdownLegA / breakdownLegB sitting at the arbitrary descendant R = z + □_l of □_m. Its consumption interface breakdownLegA_le_of_paired_bound / breakdownLegB_le_of_paired_bound demands a bound on

J(z + □_l, σ^{-1/2} v, σ^{1/2} v; a)      for every v with |v|^2 ≤ 2,

written as Book.Ch02.responseJ (Book.Ch02.cubeDomain R) (a.coeffOn R) — the bundled Chapter 2 functional on the open cube realisation openCubeSet R.

The Section 3 response observable Observable.cutoffResponseJ M l L e is, on one probability-one event and simultaneously in every direction (Observable.ae_forall_cutoffResponseJ_eq_literal), the raw functional

ResponseJ (cubeSet (originCube d l)) (σ_L^{-1/2} e) (σ_L^{1/2} e)
  (Cutoff.coefficientCutoff M.nu L ω).toFun

on the half-open realisation of the origin cube only — there is no translate parameter anywhere in the observable.

This module is the bridge between those two spellings. It is a proved local provider: it closes no source node and asserts no estimate. Every statement below is an identity (or, in the consumption lemmas, a transport of a hypothesis), so no constant is created or lost anywhere in this file.

The three components #

** Translate transport.** responseJ_cutoffFamily_eq_originCube_translate moves the response at R under the sample ω to the response at originCube d R.scale under the translated sample Cutoff.translateCutoffSample (triadicCubeShift R) ω. No rescaling is performed here and none is needed: breakdownLeg{A,B} and the observable both live at the same scale l. The scale normalisation □_l → □_0 is a separate, already proved identity (Provider/Multiscale/JCarrierRescale.responseJ_originCube_dilate).

There is no printed transport, and none is claimed. Every display in ABK26 carries z + □_l identically on both sides of the estimate; the manuscript never moves a response of this proof onto the origin cube. Its mathematical content is the pathwise change of variables the manuscript does perform elsewhere ("rescale and translate so that z + □_n appears in place of □_0"), and it is an identity for every sample: the only probabilistic ingredient, J1 stationarity, moves the almost-sure event and nothing else, so no constant, no estimate and no printed step is created, transported or consumed by it.

(b) The openCubeSet / cubeSet response identity. responseJ_cubeDomain_eq_ResponseJ_cubeSet is an equality, in both directions, at every triadic cube: the bundled Chapter 2 response on cubeDomain Q (carrier openCubeSet Q) equals the raw ResponseJ on the half-open cubeSet Q. It is CoarseGraining's Internal.Ch02.book_responseJ_eq_ResponseJ composed with CoarseGraining's responseJ_cubeSet_eq_openCubeSet_of_triadicCube (CoarseGraining/OriginCubeOpenBridge.lean), whose proof reduces the two AHarmonicFunction value sets to one another through the two CoarseGraining functors AHarmonicFunction.toCubeSetOriginCube / toOpenCubeSetOriginCube (PDE/HarmonicCube.lean, built on Sobolev/H1/OriginCubeBridge together with Sobolev/PotentialSolenoidalOriginCubeBridge), and observes that the two volume averages agree because the boundary faces are Lebesgue-null. (The transfer is not Sobolev/PotentialSolenoidalCubeBridge, which is only an ambient import of that CoarseGraining module.) Since a genuine equality is available, no inequality direction has to be selected and the transport composes in both directions.

(c) The coefficient bridge. coefficientCutoffTriadicCoeffFamily_coeffOn_toCoeffField holds at every scale L and every cube Q, by rfl:

((Cutoff.coefficientCutoffTriadicCoeffFamily M L ω).coeffOn Q).toCoeffField
  = (Cutoff.coefficientCutoff M.nu L ω).toFun .

The family's per-cube CoeffOn object carries the same pointwise representative for every cube — only its locally derived upper-ellipticity witness varies (Cutoff/CoefficientFamily.lean, the coefficientCutoffCoeffOn field toCoeffField := coefficientCutoff M.nu m ω) — so no cube-dependence and no a.e. modification enters. The Filter.EventuallyEq.rfl shape of the proved Cutoff.coefficientCutoffTriadicCoeffFamily_coeffOn_aeeq is a consequence of this, not a restriction to L = m: the family's scale argument is a free parameter, and the observable's coefficientScale argument is free as well. There is therefore no carrier obstruction at L ≠ m, and none is claimed to be bridged: Cutoff.coefficientCutoff M.nu m ω and Cutoff.coefficientCutoff M.nu L ω are genuinely different coefficient fields for L ≠ m, and passing between them is the manuscript's l.J.sensitivity step ( e.J.sensitivity.apppp), i.e. mathematics, not a spelling change.

What is deliberately not here #

Main results #

A.e. structure #

The single null set is the one produced by the all-L literal identification Observable.ae_forall_coefficientScale_cutoffResponseJ_eq_literal (Section3/Observable/CutoffResponseJ.lean), intersected over the countable type TriadicCube d after each member has been pulled back along the measure-preserving translation Cutoff.translateCutoffSample (Cutoff.map_translateCutoffSample_cutoffSampleLaw, the J1 stationarity descent). Using the all-L variant rather than its fixed-L companion Observable.ae_forall_cutoffResponseJ_eq_literal costs nothing: the two live in the same module, and the all-L one is itself only ae_all_iff over the countable index ℤ. So the coefficient scale is quantified inside the event here as well, and both countable intersections (over cubes and over scales) are already paid for. The uncountable direction quantifier stays inside each fixed-cube, fixed-scale event, where the verified common full-block representative already placed it. Every deterministic statement in this module is universally quantified with no null set at all.

References #

Component (b): the openCubeSet / cubeSet response identity #

The bundled Chapter 2 response on a triadic cube is the raw response on its half-open realisation. Book.Ch02.cubeDomain Q carries openCubeSet Q, while the Section 3 observable is written on cubeSet Q; the two responses are equal, so the transport below composes in both directions and no inequality direction has to be selected.

This is CoarseGraining's internal adapter Internal.Ch02.book_responseJ_eq_ResponseJ followed by CoarseGraining's responseJ_cubeSet_eq_openCubeSet_of_triadicCube, which matches the two AHarmonicFunction value sets and uses that the boundary faces of a triadic cube are Lebesgue-null.

Component (c): the coefficient carrier bridge, at every scale #

The cutoff family's per-cube representative is the cutoff field itself, at every scale and every cube. Cutoff.coefficientCutoffTriadicCoeffFamily assigns the same pointwise coefficient field to every triadic cube; only the locally derived upper-ellipticity witness depends on the cube. In particular the family's scale argument L is free: nothing in this identity restricts it to the scale of the enclosing cube.

Component: the translate transport #

Translation to the origin cube, at the raw carrier. Every triadic cube is the translate of the origin cube at its own scale by CoarseGraining's canonical base point triadicCubeShift, and ResponseJ is covariant under translations of the domain.

Translating the coefficient field is translating the sample. This is Cutoff.coefficientCutoff_translateCutoffSample read in the raw CoeffField spelling used by ResponseJ.

The response transport, in the observable's own spelling. The demanded bundled response of the cutoff family at an arbitrary triadic cube R is the raw response, on the half-open origin cube of the same scale, of the cutoff field at the translated sample. The comparator does not appear: the identity holds at every pair of loads p, q, hence at every comparator the switch step may choose.

The response transport, in the bundled Chapter 2 spelling. The demanded response at R under ω is the response at the origin cube of the same scale under the translated sample, both read through the cutoff family at the same coefficient scale L. This is the form in which the comparator normalization consumes the transport, since that step is stated at the manuscript's own J(·; a_m).

The almost-sure endpoint through the Section 3 observable #

The unit-D endpoint. On one probability-one event, simultaneously for every triadic cube R, every coefficient-cutoff scale L and every loading vector v, the response demanded by Breakdown's consumption interface at R is the Section 3 observable Observable.cutoffResponseJ M R.scale L v read at the translated sample translateCutoffSample (triadicCubeShift R) ω.

The coefficient scale is inside the event: the all-L identification Observable.ae_forall_coefficientScale_cutoffResponseJ_eq_literal is available at zero import cost (same module as the fixed-L one), so no null set is spent on L beyond the one intersection over the countable index ℤ that lemma already performs. This is what the J-sensitivity step needs, since it moves the coefficient scale from m to l - h on the same event.

The loads are the observable's own σ_L-pair, which is the comparator the observable pins; the free-comparator form of the transport is the deterministic responseJ_cutoffFamily_eq_originCube_translate above.

The null set is the one of Observable.ae_forall_coefficientScale_cutoffResponseJ_eq_literal, pulled back along the measure-preserving translation and intersected over the countable type TriadicCube d; the uncountable direction quantifier stays inside each fixed-cube event.

Composition with the breakdown legs #

The primal leg from a bound at the translated origin cube. A per-cube bound on the response at □_{R.scale} for the translated sample, uniform over loading vectors of squared length at most 2, bounds breakdownLegA at R.

Pathwise, and at a free comparator sigma. The comparator is left free so that the caller may choose it, but the instantiation that serves the carrier endpoint is sigma := Annealed.sigmaBar M m: that is the comparator matrix Breakdown.cutoffHomogenizationError_sq_ae_le_breakdown reads its legs at, and a leg produced at sigma := σ_{l-h} is simply not the leg that endpoint accepts. The comparator normalization is not a re-instantiation of sigma: it acts pointwise inside the response (→ 9313 replaces the loads σ_m^{∓1/2} e by σ_{l-h}^{∓1/2} e on the same cube z + □_l and the same coefficient a_m, at the price of an additive σ_{m,*}^{-1} remainder), so it is discharged inside the hypothesis h, with sigma still σ_m.

The per-cube bound is a hypothesis of the statement, not a premise of the module: nothing here asserts that such a bound holds.

The adjoint leg from a bound at the translated origin cube. The adjoint twin of breakdownLegA_le_of_originCube_translate_bound; the transported coefficient object is the transpose, exactly as in breakdownLegB_le_of_paired_bound.

The comparator reading is the same as for the primal leg: the instantiation that serves Breakdown.cutoffHomogenizationError_sq_ae_le_breakdown is sigma:= Annealed.sigmaBar M m, with the comparator change discharged pointwise inside the hypothesis h, not by instantiating sigma := σ_{l-h}.