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[Compute] Put the wrapping channel on published ground before the next ladder #576

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@LightChainr

Two computations that the literature-officer pass (#572) surfaced, both cheap, both of which should have happened before the N=580 ladder rather than after. Neither needs a new Monte Carlo run.

Part 1 — Check the torus channel against an exact polynomial, not against Monte Carlo

Akhunzhanov, Eserkepov, Tarasevich, J. Phys. A 55, 204004 (2022) (arXiv:2204.01517) give exact polynomials for square-site percolation wrapping on the torus along one direction, for L ≤ 12. The polynomials are in the supplement.

Every check the engine's wrapping channel has ever had is against another Monte Carlo estimate or against a continuum formula. This is the one place where a published closed form exists at sizes we can reach by exact enumeration.

Do: evaluate the committed wrapping observable at L ≤ 12 — by exact enumeration if that is tractable at those sizes, otherwise by the transfer engine at high statistics — and compare against the polynomial evaluated at the same p.

Why it matters: if it disagrees, the channel is wrong and every wrapping-flavoured result in the repository is downstream of a bug. If it agrees, later comparisons against Pinson at production sizes are comparisons of a checked channel against a continuum formula, which is a different epistemic object from two unchecked things agreeing.

Note the paper does not treat the NN+NNN (Sq8) matching lattice, so this checks the primary channel only.

Part 2 — Compute the Pinson/Arguin wrapping numbers, so the next ladder has a fifth competitor

Pinson, J. Stat. Phys. 75, 1167 (1994); Arguin, J. Stat. Phys. 109, 301 (2002) (hep-th/0111193).

The N=580 ladder scored A4(4i)/A4(i) against a modular weight-4 shape, the bare aspect ratio, plain area scaling, and no dependence. #572 points out — correctly, and too late — that the thin-torus behaviour of the wrapping probability π({1,0})(τ) is also a function of r that can sit near these values at three points without being either E_4 or the identity. Scoring against E_4 and reading r off the leftover is exactly how N=290 acquired a post-hoc bare_aspect_ratio.

Do: compute π({1,0})(ir) from the published Dedekind-η / Z_{m,n}(g; r) formula at g = 2/3, for r = 1, 2, 4, to enough digits to be a competitor. Cross-check against Pruessner–Moloney (cond-mat/0310361), who report agreement with Pinson to relative < 10⁻⁸ at r = 2.

Then choose one, in writing, before any re-run: either those three numbers enter the next frozen design as a named competitor, or the frozen file states that the matching-odd slope is not claimed to be a Pinson wrapping and those numbers are explicitly a non-claim. Both are acceptable; leaving it unstated is not.

One thing to keep straight while doing this

There are now three different 11/4 in play and they are not the same object:

where what it is
Ê4(2i)/Ê4(i) = 11/4 a modular weight-4 amplitude ratio — the ladder's competitor
Newman–Ziff estimator L^{-11/4} 1/ν + θ = 3/4 + 2, a finite-size convergence rate
Mertens–Ziff matching-function root, ~L^{-4} a third, different exponent

Do not let a write-up read as if a wrapping estimator converging at L^{-11/4} predicts that a spin-4 amplitude ratio equals 11/4.

Done looks like

A note in notes/ with: the polynomial comparison at L ≤ 12 (agree or not, with numbers), the three Pinson values with their cross-check, and the written choice from Part 2. No claim ledger entry — this is plumbing and theory input, not a scored block.

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    priority:P1Bounded parallel analysis or a concrete reserve direction; not all run at once.

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