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Anderson4D.DetParametrix.Core.ReductionSelectorRigidity

Rigidity of the smallest-leftmost extraction order #

The endpoint signature initially determines the interval family only up to List.Perm. For the exact R-324 fibre factorization we also need the concrete recursive order, because each step removes a sparse relative trace.

The key observation is that every interval selected later in the recursion was already fully paired in the earlier active carrier. A disjoint earlier trace does not change it, while a nested earlier trace is itself a closed fully-paired component of the larger interval. Therefore two extraction lists which are permutations have the same smallest-key head; recursion then forces equality of the lists and of their concrete trace blocks.

theorem Anderson4D.IsRelFullyPaired.lift_before_compatible_removal {m : ℕ} {κ : PartialPairing (Fin m)} {active : Finset (Fin m)} {p q : Fin m × Fin m} (hp : IsRelFullyPaired κ active p.1 p.2) (hq : IsRelFullyPaired κ (active \ relIcc active p.1 p.2) q.1 q.2) (hcompat : EarlierReductionIntervalCompatible p q) :
IsRelFullyPaired κ active q.1 q.2

A later relative candidate remains a candidate before an earlier, compatible fully-paired trace is removed.

theorem Anderson4D.extractAux_mem_isRelFullyPaired {m : ℕ} (κ : PartialPairing (Fin m)) (fuel : ℕ) (active : Finset (Fin m)) (p : Fin m × Fin m) :
p ∈ extractAux κ fuel active → IsRelFullyPaired κ active p.1 p.2

Every endpoint pair appearing later in an extraction recursion was already a fully-paired relative interval in the initial active carrier.

theorem Anderson4D.selectRel_eq_of_extractAux_perm {m fuel : ℕ} {κ κ' : PartialPairing (Fin m)} {active : Finset (Fin m)} (h : ∃ (a : Fin m) (b : Fin m), IsRelFullyPaired κ active a b) (h' : ∃ (a : Fin m) (b : Fin m), IsRelFullyPaired κ' active a b) (hperm : (extractAux κ (fuel + 1) active).Perm (extractAux κ' (fuel + 1) active)) :
selectRel κ active h = selectRel κ' active h'

Permutation of two nonempty extraction recursions forces equality of their smallest-key selectors.

theorem Anderson4D.extractAux_eq_of_perm {m : ℕ} (κ κ' : PartialPairing (Fin m)) (fuel : ℕ) (active : Finset (Fin m)) :
(extractAux κ fuel active).Perm (extractAux κ' fuel active) → extractAux κ fuel active = extractAux κ' fuel active

The deterministic smallest-leftmost recursion is rigid: if two output lists are permutations, then they are equal in their actual recursion order.

Endpoint signatures determine the actual extraction list, not merely its unordered interval family.

theorem Anderson4D.extractionBlocksAux_eq_of_extractAux_eq {m : ℕ} (κ κ' : PartialPairing (Fin m)) (fuel : ℕ) (active : Finset (Fin m)) :
extractAux κ fuel active = extractAux κ' fuel active → extractionBlocksAux κ fuel active = extractionBlocksAux κ' fuel active

Equality of endpoint extraction recursions determines the concrete sparse traces removed at every step.

Endpoint signatures determine the concrete primitive trace blocks in their actual extraction order.

Consequences for fixed R-324 moment signatures #

Equality of doubled moment signatures fixes both concrete within-half block lists, including their recursive order and sparse traces.

The terminal active carrier is the complement of the union of the concrete extraction blocks.

An endpoint signature therefore fixes the terminal active carrier.

A doubled moment signature fixes the left and right residual carriers on which the cross-copy contraction is subsequently collapsed.

Exact first-block factorization of an endpoint-signature fibre #

@[reducible, inline]

The finite fibre of partial pairings with the same complete reduction endpoint signature as κ.

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    Equality of the ordered extraction lists immediately implies equality of endpoint-role signatures.

    theorem Anderson4D.pred_add_one_eq_of_exists_relFullyPaired {m : ℕ} {κ : PartialPairing (Fin m)} {active : Finset (Fin m)} (h : ∃ (a : Fin m) (b : Fin m), IsRelFullyPaired κ active a b) :
    m - 1 + 1 = m

    A nonempty candidate set implies that public fuel m is a successor, so it can be used by the one-step ExtractionFiberAt interface.

    The endpoint-signature fibre is exactly the fixed ordered-extraction fibre used by the primitive replacement engine.

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      Exact first recursive coordinate of a nonempty endpoint-signature fibre: a complete primitive pairing on the selected block, times the remaining complementary extraction fibre.

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        Finite-sum form of the exact first-block endpoint-fibre factorization. In particular, no cardinality factor is introduced.