geolip-svd-reconstitution

Round 11 — Council Conclusion.

Phil asked for full systemic articulations, strengths and concerns, laid bare. Here it is.

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WHAT WE ARE BUILDING

An evidence-emitting eigendecomposition that extends the output signature of FLEigh to include the algorithmic conditioning history alongside the standard spectral output. This is not a new decomposition. It is the same decomposition that now tells you HOW it arrived at its answer, not just WHAT the answer is.

The motivation: the current SVAE produces perfect spectral representations (MSE 0.0000004) but downstream systems see these as opaque gradients to shift. They don't know which modes are reliable, which are contested, which spectral gaps are wide, or which boundaries the solver fought to resolve. The conduit system provides this missing evidence.

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THE SPECIFICATION

Three classes, one packet, four theorems.

FLEigh (unchanged)

The existing compilable eigendecomposition. Five phases: Faddeev-LeVerrier polynomial construction, Laguerre root-finding with deflation, FL adjugate eigenvector recovery, Newton-Schulz orthogonalization, Rayleigh quotient refinement. Public contract: forward(A) → (eigenvalues, eigenvectors). This class does NOT change. It remains the trusted reference path for production, regression testing, and any system that doesn't need conduit telemetry.

FLEighConduit(FLEigh)

Inherits from FLEigh. The base class is refactored to extract each phase into a private method (_phase1 through _phase5). FLEigh's forward() calls these phases and returns the standard output. FLEighConduit's forward() calls the SAME phase methods but captures telemetry between phase boundaries into a preallocated fixed-shape buffer. Returns a ConduitPacket.

Why inheritance over wrapper: A blind wrapper cannot see internal loop states. A separate reimplementation risks code drift. Inheritance with shared private methods gives identical arithmetic paths with zero drift risk, verified by the structural invariant that both classes call the same _phase methods.

Why not a shared _fleigh_forward_impl function: GPT proposed this; I considered it. For 150 lines of code, the function-vs-method distinction is negligible. I chose inheritance because it preserves the isinstance(obj, FLEigh) contract — any code that accepts FLEigh also accepts FLEighConduit. A standalone function would break this.

ConduitPacket

Fixed-shape tensor dataclass. Not a Python dict. All tensors batch-first, dimension-agnostic.

SPECTRAL EVIDENCE (static, deterministic functions of A):
  eigenvalues:         (B, n)     — sorted ascending
  eigenvectors:        (B, n, n)  — sign-canonicalized (see below)
  char_coeffs:         (B, n)     — elementary symmetric polynomials, monic 1 omitted

ADJUDICATION EVIDENCE (dynamic, non-reconstructible from final eigenpairs):
  friction:            (B, n)     — per-root Σ_{t} 1/(|p'(z_{it})| + δ)
  settle:              (B, n)     — per-root iteration count to |p(z)| < τ
  extraction_order:    (B, n)     — which root the solver found first, second, ...
  refinement_residual: (B,)       — ||V^T V - I||_F after Newton-Schulz (Phase 4)

RELEASE FIDELITY (cheap SVD round-trip, no decoder involved):
  release_residual:    (B,)       — ||M - U diag(S) V^T||² 
                                     (owned by SVD layer, not bare FLEigh)

Sign canonicalization: Before eigenvectors leave the packet, each eigenvector's sign is fixed by ensuring the entry with largest absolute value is positive. This resolves the gauge ambiguity that would otherwise cause the constellation to see artificial flips as meaningful geometric motion. GPT identified this vulnerability; without it, the integration with geolip-core would fail silently.

Dimension-agnostic scaling: At n=4: 38 scalars per patch. At n=8: 106 scalars. At n=16: 370 scalars. The packet structure doesn't change — only tensor shapes grow.

Research mode vs production mode: Production emits the compact packet above. Research mode optionally retains the full Laguerre trajectory (z_trajectory, pv_trajectory, dp_trajectory) and the Mstore matrices. These are behind a flag, not in the default hot path.

SVDConduit (interface defined, implementation deferred to v1.1)

Owns the release_residual computation and future decoder-side telemetry. GPT correctly identified that ||M - USVt||² belongs to the SVD/Gram layer, not to the bare eigensolver. For v1, this computation is included in the ConduitPacket for convenience but architecturally it will migrate to SVDConduit when the full round-trip conduit system is built.

Future SVDConduit will also own: per-mode reconstruction breakdown, decoder cross-attention weight summaries, and full encode→decode fidelity metrics. These require instrumenting the SVAE decoder and are out of scope for v1.

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THE THEOREM STACK

Theorem 1: Lens Preservation. FLEighConduit produces identical eigenpairs to FLEigh. Guaranteed by shared arithmetic path (same private phase methods). Verified by regression test: assert allclose(FLEigh(A), FLEighConduit(A).eigenpairs) over a representative input distribution.

Strength: Trivially true by construction. The strongest possible guarantee. Concern: If someone later modifies a _phase method without updating both forward() paths, parity breaks silently. Mitigation: the regression test catches this.

Theorem 2: Dynamic Non-Reconstructibility. friction, settle, and extraction_order are not recoverable from the final sorted eigenpairs (λ, V) in exact arithmetic. They encode the solver's algorithmic conditioning history: which roots competed, how many iterations each required, how the Laguerre dynamics navigated the polynomial landscape.

Strength: This is the genuine novel content. GPT proved that static conduits (Mstore, c, cl_k) are reconstructible from the final eigendecomposition for symmetric matrices. Only the dynamic trajectory carries excess information. Concern: At n=4 with well-separated eigenvalues, the dynamic content may be sparse — the solver converges in 1-2 iterations per root, leaving the friction tensor nearly uniform. This is the "middleground lens" problem Phil identified. Empirical validation is required to determine whether the dynamic conduits carry class-discriminative signal at D=4.

Theorem 3: Release Fidelity (future). The SVD round-trip residual ||M - USVt||² measures numerical fidelity of the eigendecomposition. The full round-trip residual (encode→SVD→decode→compare to input) measures end-to-end fidelity. Both are read-only observations that don't alter the SVAE.

Strength: The cheap SVD round-trip is free — all quantities are already available. Concern: For a well-converged FLEigh at n=4, this residual may be uniformly tiny (1e-12 or less). If so, it carries no discriminative signal. The full decoder round-trip is where meaningful variation lives, but that's v1.1.

Theorem 4: Continuity. Static conduits are continuous functions of A everywhere. Dynamic conduits are piecewise continuous, with discontinuities at root-order swaps and near-degenerate spectral collisions. Sign canonicalization resolves eigenvector gauge ambiguity within each continuous region.

Strength: Well-understood from classical perturbation theory. Weyl bounds and Davis-Kahan apply. Concern: Near-degenerate eigenvalue pairs (spectral gap → 0) cause friction to spike and extraction order to become unstable. The dynamic conduits are maximally informative precisely where they are least continuous. This is not a flaw — it's the signal — but downstream systems must be robust to these discontinuities. The constellation's soft assignment naturally handles this through assignment temperature modulation.

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INTEGRATION WITH GEOLIP-CORE

The ConduitPacket feeds into the constellation/patchwork system:

Vt → sign-canonicalize → flatten(n²) → L2-normalize → embedding on S^(n²-1)
   → ConstellationObserver.observe(embedding, mag=S_norm)
   
friction + settle → modulate assignment temperature
   High friction → lower temperature → wider soft assignment → less certain
   Low friction → higher temperature → crisper assignment → more confident

char_coeffs → additional context to patchwork compartments
   Basis-free spectral summary complements the basis-dependent Vt embedding

release_residual + refinement_residual → fidelity context
   Patches with high residual get lower trust in downstream aggregation

The judge is the evidence itself. The conduit values deterministically encode geometric purity, solver confidence, and reconstruction fidelity. No separate judge module is needed for v1. The constellation's soft assignment, modulated by friction-derived temperature, IS the geometric purity judgment. Task-specific consumers (classification heads, generative decoders, etc.) apply their own judgment formulas downstream.

Strength: This coupling is lightweight and uses existing geolip-core components without modification. The ConstellationObserver already accepts magnitude context via the mag= parameter. Friction-based temperature modulation is a natural extension. Concern: The constellation was designed for embeddings of models, not for eigenvector embeddings of 4×4 Gram matrices. The manifold geometry of sign-canonicalized flattened Vt on S^15 may have different structure than the text/image embeddings geolip-core was built for. The anchor initialization (repulsion on S^15) and patchwork compartmentalization may need tuning. This is an empirical question for the sweeping notebook.

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STRENGTHS OF THIS DESIGN

1. Zero modification to the working system. FLEigh is untouched. The SVAE is frozen. All conduit extraction is read-only.

2. Near-zero computational cost. The telemetry values are already computed inside the Laguerre loop — they're just not currently returned. The only new computation is the sign canonicalization (one argmax + one multiply per eigenvector) and the release residual (one matmul + one norm).

3. Dimension-agnostic. The packet shape scales cleanly from n=4 to n=16+. The same code works for any D without modification.

4. Theorem-backed guarantees. Preservation by construction, not by hope. The dynamic conduits are provably non-reconstructible, meaning they carry genuinely new information.

5. Compatible with existing infrastructure. ConstellationObserver, MagnitudeFlow, and Patchwork from geolip-core accept the conduit outputs without architectural changes.

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CONCERNS AND RISKS

1. Sparse signal at D=4. The solver may converge too easily for the friction/settle conduits to carry meaningful variation. The sweeping notebook must test class-discriminability of each conduit field independently.

2. Piecewise continuity of dynamic conduits. Near-degenerate patches will show discontinuous jumps in friction and extraction order. The constellation must handle this gracefully — it probably does via soft assignment, but this needs verification.

3. Eigenvector gauge residual risk. Sign canonicalization handles the dominant ambiguity, but near-degenerate eigenvalue pairs allow continuous rotation of the eigenvector basis within the degenerate subspace. This is a subtler gauge issue than sign flips. For n=4 with well-separated S values, this is unlikely to matter. For future larger n, projector-based representations may be needed.

4. Release residual may be uniformly tiny. If FLEigh's numerical precision is high enough (it wins 70/72 purity metrics), the SVD round-trip residual may be noise-floor for all patches. The full decoder round-trip (v1.1) is where meaningful release variation lives.

5. Conduit-to-constellation coupling is untested. The theory says it should work. The code says the interfaces are compatible. But nobody has actually run Vt embeddings through a ConstellationObserver with friction-modulated temperature. The sweeping notebook is the test.

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THE EXPERIMENTAL PLAN

Phil said: "We will build a sweeping notebook that tests everything in question."

EXPERIMENT 1: Signal Analysis
  Run FLEighConduit on CIFAR-10 via Freckles v40
  For each conduit field, measure:
    - variance across patches (is there signal?)
    - variance across classes (is it discriminative?)
    - correlation between fields (are they redundant?)
  
EXPERIMENT 2: Dynamic Conduit Density
  At n=4, how many Laguerre iterations does each root actually need?
  Is friction uniform or does it vary meaningfully?
  Does extraction order correlate with patch location or class?

EXPERIMENT 3: Constellation Integration
  Feed sign-canonicalized Vt through ConstellationObserver
  Measure: anchor utilization, assignment entropy, CV metric
  Compare: with and without friction-modulated temperature

EXPERIMENT 4: Classification Probe
  Simple linear probe on conduit features vs raw S values
  Does adding friction + settle + char_coeffs improve over S alone?
  This is not the downstream system — it's the proof that the evidence helps

EXPERIMENT 5: Release Residual Analysis
  Is ||M - USVt||² uniform or does it vary?
  If uniform at D=4, what is the variance at D=8?
  This determines whether release fidelity needs v1.1 urgently

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FINAL VERDICT

Build FLEighConduit. Emit the ConduitPacket. Run the five experiments. Let the data answer what theory cannot: whether the dynamic conduits at D=4 carry enough signal to justify the architecture, or whether the middleground lenses require larger D to breathe.

The theorem is sound. The architecture is clean. The risk is empirical, not theoretical. We build and we test.