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CsdLean4.LF2.Interface

LF2 ↔ LF1 interface #

Category: 3-Local (LF1 ↔ LF2 weight identity plus combined LF1_main_theorem_projective headline theorem).

Spec §6. The measure-theoretic identity linking the LF1 ontic weight μprep(π⁻¹(O)) to the LF2 projective weight (π*μprep)(O).

This is the cleanest theorem in the LF2 stack: a single application of Measure.map_apply. Its role is structural — it is the formal connection point for LF1_main_theorem_ae to speak about projective outcome weights, and the hinge by which LF2's measure bridge feeds back into the LF1 frequency theorem.

theorem CSD.LF2.lf1_weight_eq_projective_weight {SigmaSpace : Type u_1} {P : Type u_2} {G : Type u_3} [MeasurableSpace SigmaSpace] [Nonempty SigmaSpace] [MeasurableSpace P] [Group G] [MulAction G SigmaSpace] [MulAction G P] [MulAction.IsPretransitive G P] (D : SectorData SigmaSpace P G) (μprep : MeasureTheory.Measure SigmaSpace) {Oep : Set P} (hOep : MeasurableSet Oep) :
μprep (D.π ⁻¹' Oep) = projectiveWeight D μprep Oep

Spec §6.2 — the LF1 ↔ LF2 weight identity. The ontic mass of the pulled-back outcome region under a preparation measure equals the projective weight of that region under the pushforward preparation.

theorem CSD.LF2.lf1_prepMeasure_weight_eq_projective_weight {SigmaSpace : Type u_1} {P : Type u_2} {G : Type u_3} [MeasurableSpace SigmaSpace] [Nonempty SigmaSpace] [MeasurableSpace P] [Group G] [MulAction G SigmaSpace] [MulAction G P] [MulAction.IsPretransitive G P] (D : SectorData SigmaSpace P G) {Oep : Set P} (hOep : MeasurableSet Oep) :

Specialisation of lf1_weight_eq_projective_weight to the LF1 conditional preparation measure S.prepMeasure. This is the exact form consumed by a caller who has invoked LF1_main_theorem_ae for some T : S.TrialModel Ω and wants to reinterpret the limiting ontic weight as a projective weight.

Projective-first outcome constructor #

SectorData.outcomeOfProjective builds an LF1 ontic OutcomeRegion from a measurable projective region Oep ⊆ P by taking the π-preimage: Ω := D.π ⁻¹' Oep. The constructor itself requires only measurability of Oep.

The flow-projection compatibility hypothesis ∀ x, D.π (D.toOntic.Φ x) = D.π x (CSD's constraint-surface preservation reading — the ontic flow preserves projective rays) is not consumed by the constructor itself. It is consumed by the companion lemma outcomeOfProjective_preEvent to identify preEvent = Ω (i.e. to fold the LF1 one-step-ahead pullback into the plain preimage), which is what LF1_main_theorem_projective and the LF3 chain capstones need.

Architectural rationale: the Φ-π compatibility hypothesis is supplied as a lemma argument rather than as a field on SectorData — adding a field would commit all SectorData instances to the constraint-surface reading, which is LF4 instantiation work. Keeping it on the per-lemma side lets the projective-first outcome family be built at the LF3 chain capstone with a single CSD-foundational hypothesis.

noncomputable def CSD.LF2.SectorData.outcomeOfProjective {SigmaSpace : Type u_1} {P : Type u_2} {G : Type u_3} [MeasurableSpace SigmaSpace] [Nonempty SigmaSpace] [MeasurableSpace P] [Group G] [MulAction G SigmaSpace] [MulAction G P] [MulAction.IsPretransitive G P] (D : SectorData SigmaSpace P G) {Oep : Set P} (hOep : MeasurableSet Oep) :

Projective-first outcome constructor. Given a measurable projective region Oep ⊆ P, returns the ontic OutcomeRegion with Ω := D.π ⁻¹' Oep. The constructor requires only hOep; flow-projection compatibility is consumed by the companion lemma outcomeOfProjective_preEvent, which identifies preEvent = Ω. The companion lemma outcomeOfProjective_weight_eq_projectiveWeight gives the projective-side reformulation of the LF1 outcome weight.

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Instances For
    @[simp]
    theorem CSD.LF2.SectorData.outcomeOfProjective_Ω {SigmaSpace : Type u_1} {P : Type u_2} {G : Type u_3} [MeasurableSpace SigmaSpace] [Nonempty SigmaSpace] [MeasurableSpace P] [Group G] [MulAction G SigmaSpace] [MulAction G P] [MulAction.IsPretransitive G P] (D : SectorData SigmaSpace P G) {Oep : Set P} (hOep : MeasurableSet Oep) :

    Unfolding lemma: the ontic outcome region's underlying set is the projection preimage.

    theorem CSD.LF2.SectorData.outcomeOfProjective_preEvent {SigmaSpace : Type u_1} {P : Type u_2} {G : Type u_3} [MeasurableSpace SigmaSpace] [Nonempty SigmaSpace] [MeasurableSpace P] [Group G] [MulAction G SigmaSpace] [MulAction G P] [MulAction.IsPretransitive G P] (D : SectorData SigmaSpace P G) (h_flow_π : ∀ (x : SigmaSpace), D.π (D.toOntic.Φ x) = D.π x) {Oep : Set P} (hOep : MeasurableSet Oep) :

    Pre-event of outcomeOfProjective equals π⁻¹(Oep) under the flow-projection compatibility hypothesis. This is the lemma that discharges the hCorresp argument of LF1_main_theorem_projective for the constructor-built outcome region.

    theorem CSD.LF2.SectorData.outcomeOfProjective_weight_eq_projectiveWeight {SigmaSpace : Type u_1} {P : Type u_2} {G : Type u_3} [MeasurableSpace SigmaSpace] [Nonempty SigmaSpace] [MeasurableSpace P] [Group G] [MulAction G SigmaSpace] [MulAction G P] [MulAction.IsPretransitive G P] (D : SectorData SigmaSpace P G) (h_flow_π : ∀ (x : SigmaSpace), D.π (D.toOntic.Φ x) = D.π x) (μprep : MeasureTheory.Measure SigmaSpace) {Oep : Set P} (hOep : MeasurableSet Oep) :
    μprep (D.outcomeOfProjective hOep).preEvent = projectiveWeight D μprep Oep

    Weight of outcomeOfProjective equals the projective weight of Oep under the flow-projection compatibility hypothesis. Direct consequence of outcomeOfProjective_preEvent and lf1_weight_eq_projective_weight.

    theorem CSD.LF2.LF1_main_theorem_projective {SigmaSpace : Type u_1} {P : Type u_2} {G : Type u_3} [MeasurableSpace SigmaSpace] [Nonempty SigmaSpace] [MeasurableSpace P] [Group G] [MulAction G SigmaSpace] [MulAction G P] [MulAction.IsPretransitive G P] (D : SectorData SigmaSpace P G) {Ω : Type u_4} [MeasurableSpace Ω] (T : D.toOntic.TrialModel Ω) (O : D.toOntic.OutcomeRegion) (hindep : Pairwise (Function.onFun (fun (f g : Ω) => ProbabilityTheory.IndepFun f g (LF1.OnticSetup.TrialModel.trialMeasure D.toOntic T)) fun (n : ) => T.indicatorRV O n)) {Oep : Set P} (hOep : MeasurableSet Oep) (hCorresp : O.preEvent = D.π ⁻¹' Oep) :

    Combined LF1 + LF2 main theorem. Under the LF1 repeated-trial model and an LF2 sector structure with projection π, if an LF1 outcome region's pre-event coincides with the π-preimage of a projective outcome region Oep, then the empirical frequency converges almost surely to the (real-valued) projective weight of Oep under the pushforward of the preparation measure.

    This is the theorem-level consumption of LF1 by LF2: it shows that the LF1 limit is not merely an ontic volume fraction but can be reinterpreted natively in the projective measurable space that LF2 introduces. No new mathematical content beyond LF1 + the LF2 interface identity — the point is the combined statement.

    A full Born-form conclusion (‖⟨ψ, φ⟩‖²) would require an additional spec-layer correspondence between measure-theoretic projective preparations and Hilbert-space unit vectors, which LF2 does not formalise. See spec §6.4 and §8.5.