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PYTHAGORAS-4B · MANIFOLDS
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Activation geometry · frozen prover · real Lean proofs

The geometry of a proof concept

Every point is one real proof, placed by its activation at a chosen layer. Rotate it. Scrub the layer and watch the concept families condense — the depth map, as a moving manifold. Switch the metric to see why raw activations look like a blob but the model's own whitened space pulls the families apart, switch the encoder to watch a general text model fail to separate what the prover separates, and click any point to slice it back to the Lean tokens that produced it.

Concept
Encoder
Metric
Layer — scrub / play the replay
L10
drag to orbit · scroll to zoom · click a point

What you're looking at

Whitened is the model's own metric — the label-informed discriminant axes the report's 0.95 / 0.867 readouts actually live in. Raw variance is plain PCA of the activations: a graded blob, silhouette ≈ 0. That contrast is a finding — a proof concept is not a raw cluster you could stumble on; it is linearly separable only in the model's whitened space (rank-fraction ~0.40 — graded, not a hard partition).

In tactic · decision, scrub the layer: the five tactics pull apart from silhouette 0.27 at L8 to 0.34 at L20 — the model committing to its next tactic, deeper in the stack. Flip the encoder to BGE: the same 750 decision states collapse to silhouette 0.056. The general text encoder does not carry the decision; the prover does. That is the report's headline, as geometry you can rotate.

Dynamic replay: the layer morph is a continuous Procrustes-aligned interpolation of the real per-layer activations that came through the sealed substrate capture stack (frame , q-lattice 3·5·7·11). Nothing is simulated — each frame of the animation is a measured layer.

Geometry: z-score → PCA-50 → {PCA-3 | LDA-3}, Procrustes-aligned morph; t-SNE peaks; silhouette timeline · sealed 2026-09-17
Honest limits: LDA axes are label-informed (a visualization of the whitened metric, not a held-out accuracy — those are the report's LOO numbers). Per-sample last-token / decision-state, not per-token. Domain set carries no per-sample statement text. 480 domain / 495 tactic-statement / 750 decision points, one prover.