A change with nowhere to be
Worth reading first: Where a handover sits.
A handover is the rise at which a lattice’s two contact steps change places: above it one family has the shorter hop across the surface and below it the other does. A band is the stretch of rise around one, over which the counted pair and the settled divergence hold still.
The claim the handover thread rests on is that the survivor does not change there. When a cut wrecks a stem, the family whose hop the wrecked run holds rigid is not decided by which hop is currently shorter — and the sharpest form of that is that the rise where the ordering changes is not the rise where the survivor does.
What the claim had behind it
Nineteen located changes on the golden 8/13 band, none of them at its handover. Zero changes on the Lucas 7/11 band, which contributes a vacuous confirmation and was reported as vacuous rather than counted.
That is a strong negative. The changes on the first band sit seven to fifty-seven rises below the handover, at three separate rises for the three offsets that change, and none of them is nearer than seven rises to the crossing. The same band’s alternation turned out to be speckle rather than a period, so the changes are not evenly spread either — they cluster below the crossing and thin out further down.
Nineteen chances to land on one rise and none of them did. Under a coin that puts a change anywhere on a 126-rise band, that is unremarkable — the handover is one rise of 126 — which is why the claim is stated as a negative rather than as a surprise.
The flag
The sweep marks a change at the handover when the two rises it is bracketed between sit either side of the handover rise. That is the only test available: a change is not observed at a rise, it is observed between two rises where the answer differs.
Across two bands the flag never fired. On the third band it fires once, and the firing is the subject of this essay.
The bracket is not two adjacent rises. It runs from 0.01605 to 0.01497 — a hundred and eight steps of the grid the rises are named on, twenty rises of the band — and the handover at 0.01558 is inside it because nearly everything on the band is inside it.
Why the bracket is so wide
Because a change of surviving family can only be bracketed between two rises at which that offset wrecks, and offset 5 on this band wrecks at 28 of 112 rises.
At 0.01605 it wrecks and keeps 20. Then it recovers at every rise for the next thirty-four, which carries it past the handover and well below it. At 0.01497 it wrecks again and keeps 5.
Nothing was observed in between because there was nothing to observe. A cut that recovers leaves a stem with no rigid lag to report, so those thirty-four rises are not rises where the answer was 5 or 20; they are rises where the question has no answer.
What is at the handover rise itself
One wrecking cut. At 0.01558 the only offset that wrecks is 4, and it keeps 5 — as it does at the rise above and the rise below and at 111 of the band’s 112 rises.
So the direct reading at the handover is available and it shows nothing changing. The offset that changes is not wrecking there; the offset that is wrecking there does not change.
That is the honest summary and it is neither a confirmation nor a counterexample. The band has one changing offset and it is silent across its own handover.
The flag is measuring the wrecking set
Which is the finding. A test of the form does the answer change at the handover assumes the answer exists on both sides of it, close enough that a change between them is a change there.
On this band it does not. The flag fires because the bracket is wide, and the bracket is wide because the offset stops wrecking — so what the flag reports is a property of the wrecking set rather than of the survivor.
Nothing in the sweep distinguished the two cases before, because the first two bands never produced a wide bracket: on the golden 8/13 the changing offsets wreck at 123, 110 and 22 of 126 rises, so their brackets are one to a few rises wide.
A distinction the instrument could not make
Two things can be true of a change, and until this band they had never come apart.
Located: the change is bracketed between two adjacent rises, so its position is known to one step of the grid and can be compared with the handover’s.
Flagged: the bracket contains the handover, whatever its width.
On nineteen changes both were available and the flag was never set. On the twentieth the flag is set and the location is not available, and the flag is what the sweep reported.
What a fixed instrument would say
That this band produces no test of the claim. Its one changing offset is silent across the handover, so the claim is neither supported nor contradicted here.
The tally therefore stands at nineteen tests, all negative, one band with nothing to say and one band with nothing to change. That is a weaker position than twenty of twenty, and it is the position the evidence supports.
Reporting it that way costs the round a confirmation it would have been entitled to claim under the old reading, which is the reason for writing it down rather than adjusting the flag quietly.
Why the test is hard to make at all
The two quantities live at different resolutions and neither can be moved much.
A handover is geometry. It is computed from hop lengths on an intact stem, so it can be located to any grid anybody cares to walk — on one Lucas rung it is now known to one part in ten thousand for the cost of a few hundred stems and no cuts at all.
A survivor is a cut. It exists only where a removal wrecks the stem, and where it wrecks is itself a function of the rise. So one side of the comparison is continuous and arbitrarily fine, and the other is a scatter of points whose spacing nobody controls.
Where the test can be made cleanly
On a band whose changing offsets wreck densely. The golden 8/13 is that band: its offset 8 wrecks at 123 of 126 rises, so every one of its thirteen changes is bracketed within a rise or two, and the comparison with the handover is a comparison of two well-located rises.
That is where the nineteen negatives come from, and it is worth noticing that they come from one band. The claim is scored on nineteen changes and one lattice family, which is a narrower base than the count suggests.
A fourth band with a densely wrecking changing offset would double the base. Whether the Lucas 4/7 provides one is not predictable from anything here.
The rung where both are located
There is one object on the ladder where both quantities are known to one step of the five-decimal grid, and it is not a band. On the Lucas 7/11 rung, the two contact steps cross between 0.00804 and 0.00803, and the rise at which a cut first keeps the larger family sits between 0.00640 and 0.00639.
Those are a hundred and sixty-four steps of the grid apart, which is 45 per cent of the rung’s whole span. Both are located to one step, so the separation is larger than the two locations put together by two orders of magnitude.
That is the cleanest form of the claim available anywhere on this site, and it is a rung rather than a band because a rung can be walked and a band is a fixed set of rises.
What the band design is actually good for
Counting. A band cut at every rise tells how many changes there are, which offsets have them, and whether they form islands — and none of that needs the changes to be located against anything.
Placing them against a handover is a second question the design answers only where the wrecking set cooperates. The design was not built for it: it was built to test whether the survivor is constant across a band, and the handover comparison came later.
So the right reading is that a band sweep produces a census of changes and, incidentally, a comparison with the handover on the changes whose brackets are narrow.
The same shape, one level down
This is the second time in one round that an answer has turned out to exist only where a cut wrecks.
On the Lucas 7/11 rung, offset 8 changes the family it keeps and cannot be located — it keeps 7 at 0.0065 and 11 at 0.00637 and does not wreck at the three rises between. The rise the search does locate to one grid step is the rise at which the lattice first keeps the larger family anywhere, which is a different quantity.
Two different sweeps, two different questions, the same limit: an offset’s own answer is sampled at the rises where its cut wrecks, and that sampling is not under anybody’s control.
Why not sweep more finely
Because it would not help. The gaps are not gaps in the sampling; they are stretches where the cut recovers, and cutting at every hundred-thousandth instead of every two-thousandth would produce more rises at which offset 5 recovers.
The only thing that would fill them is a different offset, and a different offset is a different question — the answer at offset 4 across the handover is already known and it does not change.
That is what makes the limit structural rather than a matter of resources. It is the object that is silent, not the instrument.
What would change the answer
A band where an offset changes its family at two adjacent rises either side of a handover. That is a positive result and it would refute the claim outright, and nothing rules it out.
Or a fourth band with dense changing offsets and no change at its handover, which would move the claim from one lattice family to two.
Both are the same half-hour of machine time on the Lucas 4/7 band, and neither is predictable. That is the state a claim should be left in: with a stated test that could go either way and a cost attached to it.
What a wrecked cut is, and why it can vanish
A removal wrecks a stem when the pattern above the hole never returns to the arrangement it had. Whether it does is not a property of the offset alone: the same offset at two rises a few thousandths apart can wreck at one and recover at the other, with the counted pair, the divergence and the front all unchanged.
That is the fact this essay is downstream of. Every band cut whole has shown it, and on the third band it is at its most thorough — not one of the three offsets wrecks at every rise, where the first band has one that does and the second has three.
So the set of rises at which a given offset has an answer is itself a scatter, and the scatter is what sets the resolution of every question about that offset’s answer. Nothing about the design chooses it.
The arithmetic of the bracket
Twenty rises of the band, which at a step of two parts in a thousand is a ratio of 1.041 in the rise — from 0.01605 down to 0.01497. The handover sits at 0.01558, which is 47 per cent of the way along that stretch in the logarithm.
Put differently: the bracket covers 18 per cent of the whole band, and the band covers 23 per cent of its rung. So the change is located to about four per cent of a rung, against a handover located to better than a tenth of a per cent of one.
A comparison between a quantity known to four per cent and one known to a tenth of a per cent is a comparison whose answer is decided by the first, and the first is not under control.
Why the flag was written that way
Because on the band it was written for, it was right. Every change on the golden 8/13 band is bracketed within a rise or two, so the bracket contains the handover and the change is at the handover were the same statement there, and the simpler one was coded.
That is the ordinary way a reading acquires a hidden assumption: it is written against the case in hand, it is correct there, and the assumption is invisible until a second case violates it. The same thing happened to the count of exceptional chains, where three or more exceptions and no balanced pair were treated as one description and turned out to differ on two rows.
The repair in both places is the same: separate the two readings, report both, and say which one a claim is being made on.
What the sweep does report correctly
Everything about the change itself. That it happens, that it is at offset 5, that the family it goes to and comes back from is 20, that it happens twice and that both rises sit above the handover.
The two rises at which offset 5 keeps 20 — 0.01625 and 0.01605 — are read directly and are not brackets. It is the return to 5 that is bracketed, because the offset is silent from 0.01605 to 0.01497.
So the picture is: two isolated rises with an unusual answer, a long silence, and then the ordinary answer again. What cannot be said is where inside the silence the ordinary answer resumed.
That is also why the nine-rise sample found nothing on this band: a sample that visits ten rises at a step of fourteen is very unlikely to land on either of two isolated rises, and it landed on neither.
The general shape of the limit
A quantity that exists only where something else happens can be sampled no more finely than that something else. Here the quantity is the family a cut keeps and the something else is the cut wrecking, and the wrecking set is not under anybody’s control.
That is not a resolution problem and cutting more rises does not fix it. Cutting every hundred-thousandth of the band instead of every two-thousandth would produce more rises at which offset 5 recovers, and its silence across the handover would be just as complete.
The same limit turns up one level down in the same round, on a rung rather than a band, where an offset changes the family it keeps and cannot be located because it is silent at three consecutive rises inside its own bracket. Two sweeps, two questions, one structural constraint — and naming it in both places is worth more than either instance.
What could be tested instead
The claim is about a handover, and a handover is geometry: it can be located to any grid anybody cares to walk, for the cost of one grown stem per rise and no cuts.
So the useful move is to pick the object where the other side is also well located. On the Lucas 7/11 rung both the crossing and the rise at which a cut first keeps the larger family are known to one step of the five-decimal grid, and they are 164 steps apart. That is a test of the same claim with neither side bracketed, and it is the strongest form of it anywhere on this site.
A band gives the better-controlled comparison — the divergence is held still — and a rung gives the better-located one. Neither subsumes the other, which is the argument for keeping both.
What is recorded
That a change of surviving family was flagged at a handover for the first time across three bands cut whole; that the change is bracketed across twenty rises and a hundred and eight steps of the grid; and that the handover is inside the bracket because the offset does not wreck anywhere near it.
That the claim is therefore untested on this band rather than confirmed or contradicted, and that the tally is nineteen located changes, all negative, from one band.
And that the flag as written cannot tell a change at a handover from a change bracketed across one, which is a defect in the reading rather than in the sweep, found by a band that produced the case.
What links here
Computed from the collection, not written here: the essays that point at this one.
Shares its objects with
Essays that name at least two of the same things, and that neither author linked.
- A period the grid invented — both name ablation, artefact, claim testing, discretisation, honest limits, measurement, negative result, refusal, resolution
- A band with nothing inside it — both name ablation, claim testing, contact family, handover, honest limits, negative result, resolution
- A list that was a rounding — both name artefact, claim testing, discretisation, honest limits, measurement, negative result, resolution
- A median that is an exception — both name artefact, claim testing, honest limits, instrument setting, measurement, negative result, refusal
- A removal that changes nothing — both name ablation, artefact, claim testing, discretisation, measurement, negative result, resolution
- A window nobody aligned — both name ablation, artefact, claim testing, honest limits, measurement, negative result, resolution
Named objects
A flat tag is an object no other essay names yet.
AblationArtefactClaim testingContact familyDiscretisationHandoverHonest limitsInstrument settingMeasurementNegative resultRefusalResolution