Math Mapgenerated 2026-10-25 · a354234
PUBLIC BUILD

run 057Settled

Birch and Swinnerton-Dyer read the rank of an elliptic curve as a growth exponent — the slope of log ∏_{p≤X} N_p/p against log log X. That is the same instrument runs 051–056 use on carpets: a global exponent fitted from local counts across a few decades of scale, where pair slopes drift. On curves whose ranks are known, over four decades of X, does the slope read the rank, and does the drift behave like a finite-size correction that shrinks with scale?

slug
bsd-euler-product-slopes
state
run
created
2026-09-29
sealed
2026-09-29
measured
2026-09-29
builds_on
[056, 055]
concepts
[elliptic-curves]
statistic
New directory R28_bsd_euler/ (Lab_Tree_Model or any compute chat with PARI). Five Cremona curves of known rank: 11a1 (r = 0), 37a1 (1), 389a1 (2), 5077a1 (3), 234446a1 (4). For each, P(X) = ∏ N_p/p over primes p ≤ X of good reduction, N_p = p + 1 − a_p with a_p from PARI's ellap; y(X) = ln P(X), t(X) = ln ln X, evaluated at X = 10^k for k = 3, 4, 5, 6, 7, 8. The fitted slope b = least-squares slope of y on t over k = 4…8 (five points). Pair slopes b_k = (y(10^{k+1}) − y(10^k)) / (t(10^{k+1}) − t(10^k)) for k = 3…7. Controls before any product is formed: (i) a_p for 11a1 at p = 2, 3, 5, 7 equals −2, −1, 1, −2; (ii) PARI's ellanalyticrank returns 0, 1, 2, 3, 4 for the five curves. Reported, not sealed: y(X) at every decade, the pair slopes, the residual of the five-point fit, wall time.
script
R28_bsd_euler/run057.sh, R28_bsd_euler/euler057.py, R28_bsd_euler/analyze057.py
artifacts
[R28_bsd_euler/RESULTS057.md, R28_bsd_euler/slopes057.json]
outcome
confirmed
next
The carpet fits have three sizes and two pair slopes, which cannot tell a monotone drift from an oscillation like the one seen here. Would a fourth size (L = 19683) or interleaved sizes (L = 243, 2187) on one carpet show whether its pair slopes oscillate? | builds_on: 057
source
../lab/runs/057-bsd-euler-product-slopes.md

Prediction(1) The fitted slopes are in strict rank order across all five curves. (2) |b − r| ≤ 0.35 for every curve. (3) For at least four of the five curves the last pair slope b_7 is closer to r than the first pair slope b_3 — the drift is a finite-size correction that shrinks with scale.

Falsifierany of — two curves whose ranks differ by one have fitted slopes out of order; or |b − r| > 0.7 for any curve (four decades of X, a range of only 0.69 in ln ln X, cannot read the rank to within one-half). A failed control withdraws the run. Between prediction and falsifier on any clause is unanticipated.

VerdictCONFIRMED 2026-09-29, scored as written. Both controls passed (11a1's a_p = −2, −1, 1, −2 at p = 2, 3, 5, 7; ellanalyticrank 0, 1, 2, 3, 4; conductors match labels). Clause 1: fitted slopes −0.055, 0.959, 1.719, 3.203, 3.929 are in strict rank order. Clause 2: |b − r| = 0.055, 0.041, 0.281, 0.203, 0.071, all within 0.35. Clause 3: the last pair slope is closer to r than the first on all five curves (distances 0.291→0.142, 0.711→0.254, 0.305→0.099, 1.171→0.984, 1.004→0.048). No falsifier fired. The body records that clause 3's gloss — a drift that shrinks as a finite-size correction — is not what the pair slopes show: they swing by up to ±1 between neighbouring decades and are not monotone.

Sealed 2026-09-29, before any a_p was computed for this run (codifier). Known at sealing: the ranks of the five curves (Cremona's tables; checked by control ii), the history of the conjecture (the slopes were found numerically in the 1960s and converge slowly), and runs 051–056. Not known: any product value or slope at these ranges. No attribution for the convergence theory is relied on; the prediction is made from the instrument's geometry, not a cited theorem.

Why it is a test and not an illustration. The whole span of four decades of X is 0.69 in ln ln X. With a rank-one difference worth only 0.69 in y across that span, the oscillating part of y(X) — driven by the curve's L-function zeros — could reorder neighbouring ranks or pull a slope half a unit off. Clause (2)'s 0.35 is a bet that it does not; the falsifier's 0.7 is where the reading would be unusable. Clause (3) is the transferable question: in runs 053–055 the carpet pair slopes drifted monotonically with L, and the scoring treated that drift as finite-size. Here the true exponent is known, so the drift's direction can be checked against an answer.

What the outcomes mean. Confirmed: the slope-of-a-log-log-fit instrument reads a known exponent at this range, and its pair-slope drift shrinks toward the answer — support for reading the carpets' drift the same way. Falsified on order or size: four decades is too short for this instrument even with an exact answer available, and the carpet readings, which span log L over a similar number of decades, deserve the same doubt. Unanticipated on (3) alone: the drift is not a monotone correction, and "the asymptotic value may be lower" (053's caveat) is not a safe reading of drift.

---

Scored 2026-09-29 — confirmed

Results: R28_bsd_euler/RESULTS057.md, slopes057.json (commit 651d50e). PARI 2.17.2 via cypari2 2.2.4; one forprime + ellap sweep to 10^8 per curve, 212–218 s each, five in parallel.

curverb (k = 4…8)b_3b_4b_5b_6b_7
11a10−0.0550.291−0.0840.130−0.207−0.142
37a110.9591.7110.9460.8120.9961.254
389a121.7192.3051.1691.7962.0162.099
5077a133.2031.8293.5262.9303.8432.016
234446a143.9295.0044.1993.3804.2584.048

What it settles. Over four decades of X — 0.69 in ln ln X — the five-point fit reads every rank to within 0.3 and orders all five. The instrument works at this range when it is given five sizes.

What it does not, stated because the outcome word would otherwise carry it. Clause 3 passed as written (first pair slope versus last), but its gloss does not hold. The pair slopes are not a correction shrinking toward r; they oscillate by up to ±1 between neighbouring decades — 5077a1 goes 1.83, 3.53, 2.93, 3.84, 2.02 — and the first-versus-last comparison passed partly by where the oscillation happened to land. A single pair slope is not a reliable reading of the exponent here; the multi-point fit is.

What it means for the carpets. Runs 053–055 read 1/ν from three sizes, with two pair slopes, and 053 and 055 read the downward drift of those pair slopes as "the asymptotic value may be lower". This run shows that with a known answer, pair slopes can swing both ways, so two of them cannot distinguish a monotone drift from an oscillation. The carpet pair slopes move by 0.02–0.05, far less than here, so the carpets' fitted values are not in doubt from this — but the drift caveats in 053 and 055 are unsupported readings, not findings. The next: asks for the size that would tell them apart.

Pointers corrected 2026-10-05 (codifier; no sealed field, score or number is changed). The script: line was written with the seal, before the script existed, and read: script: R28_bsd_euler/ (to be written by the compute chat). It now names what was written and committed: R28_bsd_euler/run057.sh, R28_bsd_euler/euler057.py, R28_bsd_euler/analyze057.py. Found by sync_cases.py's record-field check (docs/REPO-AUDIT.md 5.4).

generated 2026-10-25the lab index