| what the corpus calls it | the standard name | where |
|---|---|---|
| the fold F, “rank-1 Jacobian loss” | the Jacobian of a vector-valued map, and its rank | D p. 140 |
| transverse eigenvalue μmax | eigenvalue of the linearisation at a fixed point | D §4.2 · H p. 412 |
| “the linearisation at Γ” | first-order Taylor expansion | D p. 140 |
| curvature at the threshold κ* | the Hessian | D p. 136 |
| G = U∘F∘K∘C | the chain rule for composite maps | D p. 146 |
| descent on the potential Φ | gradient descent | D p. 226 |
| stochastic forcing along the orbit | stochastic gradient descent | D p. 226 ff |
| constrained basin conditions | Lagrange multipliers | D p. 226 ff |
| kernel-checked derivative chains | automatic differentiation | D p. 164 |
| “same normal form, different parameters” | similarity of matrices | H p. 274 |
| diagonal normal form | diagonalizability | H p. 270 |
D = Deisenroth · H = Hefferon. Printing-specific; the script re-locates them against your copy and exits non-zero if a row moves.
| level | what the corpus has | the standard object |
|---|---|---|
| discrete | the g-series 0, 2, 6, 33, 64; rfl on numerals | recurrences; what a definitional equality is worth |
| probability | “the basin”, “converges to Γ” | convergence — and in which sense |
| dynamics | Γ, T* = 2π, μmax, ε₀ = 1/3 | limit cycle, period, Floquet multiplier, Grönwall radius |
| verification | sorry, “0 sorry”, “domain axiom” | five words for one hole, not interchangeable |
| rung 28 | “an index”; e−4π proposed as one | K-theory classes and the index pairing |
| rung 33 | spectral triples — 31 mentions | the spectral triple, with its floor under it |
The rest are correspondences of practice. Similarity is not: two matrices are similar exactly when they represent one linear map in different bases (H p. 274). That is what the Coherence Bridge means to claim, stated in a standard term with a decision procedure attached — so it was run.
tools/coherence_similarity.py parses the table out of book4/hub.html — not transcribed — and finds eleven rows carrying both μ and ω. Near Γ each is a 2×2 system with eigenvalues μ ± iω.
| test | invariant | matching pairs |
|---|---|---|
| linear similarity (same map, new basis) | the eigenvalue pair | 0 of 55 |
| similarity up to time-rescaling | the ratio μ/ω | 0 of 55 |
| topological conjugacy [standard] | being a spiral sink | 11 of 11 |
The closest pair under the most generous reading is Immune adaptation and Market volatility, μ/ω = −2.4444 against −2.3929 — near, and not equal. Nothing else is within 0.11.
So the claim is true at the level where it carries no information, and false at every level where it would. Every 2D linear spiral sink is topologically conjugate to every other; eleven of eleven rows qualify, and so would any eleven damped oscillators picked at random. The moment the test asks for anything finer — the same map in a new basis, or even the same map after rescaling the clock — the count is zero.
Ch 20 already says the honest version: “six systems have been shown to admit the same normal form with different invariants … it is not yet a categorical equivalence, and the difference matters.” This adds the number. Four other pages still carry the unhedged form — vol2-dashboard.html, ch-e-gtct.html, ch24-seed-sentences.html and the TO deploy — and are not edited here. [OPEN]