From c60340b1dee34585d1e05f6a80470b350343efd5 Mon Sep 17 00:00:00 2001 From: ReaperOfVeriod Date: Sun, 11 Oct 2026 04:13:55 +0200 Subject: [PATCH] Correct the post-shrub 368 stride: real, but in one 15 KB window The claim that the post-shrub region has a 368-byte period throughout is wrong. Re-measured over the whole region the curve is flat and near noise: stride 8 +0.027 stride 12 +0.023 stride 148 +0.009 stride 340 +0.018 stride 368 +0.018 stride 632 +0.020 Nothing peaks at 368, and the 0.1110 recorded earlier does not reproduce under any sampling convention tried. Where the structure is: scanning 8 KB windows at 1 KB steps for a 368-excess above 0.15 finds one substantial region, region+41984..+57344, 15360 bytes, plus a 4 KB patch at region+650240. Within that window 368 is unambiguous -- +0.315 against +0.284 at 736, with 364, 372 and 732 all at noise. 41 whole records, mean 16 distinct values per position, and nine positions exactly constant and zero: 329-336 and 340. Twenty-five positions have 3 or fewer distinct values, clustered in 325-349, which is a tail rather than scattered padding. Corrected statement: a 15360-byte window of the post-shrub region is a table of 41 records at stride 368, each with a roughly 43-byte tail whose fields are mostly zero. The surrounding 675 KB is not that table. What went wrong before: the original measurement was taken over a window where 368 held, then reported as a property of the region. That window holds 41 of 1841 records, and averaging it over the region flattens the peak to the noise floor. The re-verification checked the stride but not whether it applied uniformly, so it confirmed the number without testing the claim attached to it. --- docs/formats/core-data-regions.md | 55 +++++++++++++++++++++++++++++++ 1 file changed, 55 insertions(+) diff --git a/docs/formats/core-data-regions.md b/docs/formats/core-data-regions.md index 7854f82..ab38c29 100644 --- a/docs/formats/core-data-regions.md +++ b/docs/formats/core-data-regions.md @@ -670,3 +670,58 @@ multiples confirm it), and the alignment with four constant zero positions is solid. What sits in those bytes is not a record layout, and the two findings are in tension in a way this project has not otherwise seen: a confirmed period that is not a record boundary. + +## Correction: the 368 stride is real, but confined to one ~15 KB window + +The claim earlier in this file that the post-shrub region has a 368-byte +period *throughout* is wrong. Re-measured over the whole region, the +autocorrelation curve is flat and near noise: + +| stride | excess over matched shuffled control | +|---|---| +| 8 | +0.027 | +| 12 | +0.023 | +| 148 | +0.009 | +| 340 | +0.018 | +| **368** | **+0.018** | +| 632 | +0.020 | + +Nothing peaks at 368. The figure of 0.1110 recorded earlier does not +reproduce under any sampling convention tried (step 1, 2 or 4 through the +window; all give ~0.018). + +**Where the structure actually is.** Scanning 8 KB windows at 1 KB steps for +a 368-excess above 0.15 finds exactly one substantial region: + + region+41984 .. region+57344 = 15,360 bytes (abs 16089024..16104384) + +plus a 4 KB patch at region+650240. Everything between and around is flat. + +**Within that window the 368 stride is unambiguous:** + +| stride | excess | +|---|---| +| **368** | **+0.315** | +| 736 | +0.284 | +| 364 | +0.024 | +| 372 | +0.021 | +| 732 | +0.027 | + +The peak is sharp, 736 confirms it as a multiple, and the neighbours are at +noise. + +**Record shape.** 41 whole 368-byte records. Mean distinct values per +position is 16 of 41, and **nine positions are exactly constant and zero**: +329 through 336, and 340. Twenty-five positions have 3 or fewer distinct +values, clustered in 325-349 -- a tail region rather than scattered padding. + +So the corrected statement is: a 15,360-byte window of the post-shrub region +is a table of 41 records at stride 368, each with a roughly 43-byte tail +whose fields are mostly zero. The surrounding 675 KB is not that table. + +**What went wrong before.** The original measurement was taken over a window +where 368 held and then reported as a property of the region. The 15 KB +window holds 41/1841 of the region's records, and averaging that over the +whole region flattens the peak to the noise floor. The re-verification pass +checked the stride but not whether it applied uniformly, so it confirmed the +number without testing the claim it was attached to.