A transition and not a slope
Worth reading first: Both walls of the slot.
Two rungs in the slot table are described as going free — the second removal costing nothing over the larger one alone. The word was earned by two rows sitting within half a degree of their larger single removal while every other row sat eight degrees or more away.
Whether that word names something depends entirely on what the quantity does between the rows that have it and the rows that do not. The table has no rows in between: it samples each rung at three positions, and on the rung in question the nearest row on the other side is a third of a rung away.
Two readings with the same evidence
Reading one: the fourth cell’s cost declines gradually down the rung, and half a degree is a line drawn across a continuum. On that reading free is a bucket and the two rows in it are the two that fell below the line.
Reading two: the cost is one value and then another, and half a degree is a gap rather than a threshold. On that reading there is a rise at which a slot loses a wall, and it is a thing to name.
Three samples a rung are consistent with both, which is why the question needed more.
The measurement
Twenty-nine positions on the golden 5/8 rung, from 61 to 97 per cent of it, ten at three per cent apart, ten at one per cent, and nine at the five-decimal grid.
The fourth cell’s cost is 163.59 degrees at every position above a rise of 0.00998 and between 8.91 and 13.83 degrees at every position below 0.00997. There is nothing in between.
The lower stretch is not flat, and that is worth saying precisely: it climbs gently from 8.91 to 13.83 degrees across a third of a rung, in step with the larger single removal it is tracking. What is flat is the upper stretch, at one value to the last digit of the grid across every position above the change.
What a slope would have looked like
A quantity declining from 163 degrees to 12 across a third of a rung, through the positions at 0.00999, 0.00998, 0.00997 and 0.00996, would have shown values at 120, 80 and 40 degrees somewhere.
Twenty-nine positions leave room for that and it is not there. The cost is flat at one value, falls by 154 degrees in one step of the grid, and is flat at the other.
Half a degree is a gap after all
Which settles the threshold question. The two free rows sit at 0.0 and 0.2 degrees from their larger single removal and everything else is 8 degrees or more away — and now the whole stretch below the transition sits at 0.0 to 0.24 degrees.
So the half-degree line is separating two populations rather than cutting one, at every position on this rung. That was asserted when the line was chosen and it is now measured.
And the word names something
A rise at which the second wall of a slot stops costing anything, on the golden 5/8 rung, between 0.00998 and 0.00997.
That is a specific rise on a specific rung and it is the first thing in this thread that the word free points at rather than describes. Whether other rungs have one, and where, is the obvious next question and is fifteen minutes each.
The Lucas 3/4 rung is the one to do, since it is the other rung with a free row that is not free throughout. The Lucas 1/3 rung is free at every position it has, and its rows are free by cancellation rather than by anything the rise decides.
What has to be ruled out
A jump of a hundred and fifty-four degrees invites one objection above all others, and it is that the lattice changed. A rise a thousandth away could in principle be a different rung, a different pair, a different anything.
Five quantities were read on both sides for exactly that reason, and all five are identical.
The two walls
5 and 8, on both sides, counted from the points of the very stem the cuts are made in rather than assumed from the rung.
That distinction matters more than it looks. The design’s whole content is naming two offsets, and an offset read off the wrong stem names an organ that is nobody’s neighbour while every other number in the row stays plausible.
The settled divergence
137.438 degrees, on both sides, which is the intact stem’s own answer and is what makes the two rises the same lattice in the sense this collection uses the word.
A rung is a stretch of rise over which the counted pair holds, and the divergence moves slowly across one. Two rises a thousandth apart give divergences that agree to three decimal places, which is what they do here.
The block
2, on both sides. The block is the period of the orbit the cut stem’s placements fall into, and it is the coarsest description of what a cut does.
A cut that opened a different block would be a different kind of damage. The same block on both sides means the transition is not a change in what the cut does to the run, only in where one organ lands. A block that is the azimuth grid rounding a constant is the failure this reading would otherwise be open to, and a block of two on both sides is not that.
Which cells wreck
All three removals wreck the stem on both sides. So the transition is not a stem crossing from recovering to wrecking, which is the other binary in this thread and the one that moves across a band all the time.
Had that been what changed, the fourth cell’s fall would have been the difference between a displacement and no displacement rather than between two displacements.
The lags left rigid
5, 10 and 15, on both sides. Those are the lags whose hop the cut stem still holds after the doubled removal, and they are the closest thing the design has to a description of what survives.
The same three on both sides is the strongest of the five, because it says the arrangement the cut stem ends up in has the same structure above and below the transition.
Rigid lags are the same object the ablation census indexes by when it names a surviving family, read here off a stem with two organs removed rather than one.
So one organ, and only one
Five quantities held and one moved. The first organ placed after the doubled cut goes to +163.59 degrees above the transition and −9.14 below it.
That is what the transition is, and it is narrower than the word free sounds. A slot losing a wall is a statement about a placement, on a lattice that is otherwise unchanged.
The sign check
Both values sit exactly on the azimuth grid — 698 steps and 39 steps of 1,536 — and they have opposite signs.
That rules out the reading that would have made the whole thing an artefact: a folded angle creeping past a half turn and coming back the other way. Such a thing would give a large positive then a large negative, not a large positive then a small negative.
What a fold can hide
Worth a paragraph on its own, because folding is used everywhere in this collection and its costs are rarely stated. A displacement is folded into a half turn either way because a lattice and its mirror are one lattice under this rule.
The price is that two very different placements can fold to nearby numbers, and that a sequence of placements crossing a half turn looks like a reversal. Every claim about a folded quantity’s size is safe; claims about its change need the unfolded values checked, and here they were.
What is not ruled out
One thing, and it is the subject of its own reading. The five held quantities are all read early or read from the intact stem. What the wrecked run ends up doing is a sixth quantity and it is not stable on this rung at all.
So a reader wanting the transition changes one organ and nothing else about the run cannot have it. What can be had is that the transition changes one organ and none of the five things that would have made it a change of lattice.
The value of asking what kind
The measurement cost three minutes and it changed a word from a bucket into a name. That is the return on asking what kind of change is this? rather than where is the change?
The second question is what three samples a rung answer. The first needs enough positions that a slope would have shown, and enough that the flat stretches on either side are flat rather than assumed.
Where the same question was asked and answered the other way
Not every quantity in this collection turns out to be a step. The settled divergence down a rung is a smooth curve, and the width of a band is a smooth function of the curvature at its handover.
So the answer here is not a house style. It is a measurement, and the two shapes are distinguishable by exactly this method: sweep finely and look for the intermediate values.
What twenty-nine positions can and cannot say
They can say the change is not gradual over any stretch wider than one grid step. They cannot say it is instantaneous, because the grid is where this collection’s descriptions stop.
Between 0.00998 and 0.00997 there are rises this rule would place organs at perfectly happily. The sweep does not go there because the ladder is named on the five-decimal grid and a rise finer than that is a rise no other file in the collection could refer to.
Why a flat stretch is evidence too
The upper stretch is worth as much as the step. From 15 per cent of the rung down to 61 per cent the fourth cell’s cost is 163.36, 164.06, 163.59 and 163.59 degrees — four positions spanning nearly half a rung, agreeing to within three quarters of a degree.
A quantity that were sliding towards a transition would not do that. It would climb or fall as the transition approached, and the last position before the step would be closest to the value after it. Here the position immediately above the step reads exactly what the position at 15 per cent reads.
So the picture is two plateaux rather than a ramp with steep ends, which is the strongest form the finding takes.
What the earlier design would have had to do
Locating this with the three-per-rung design would have needed the samples in the right place by luck. At 15, 50 and 85 per cent the change at 61 falls between the second and third, so the design reports a change between 50 and 85 per cent — a bracket a third of a rung wide.
That is what it did report, in the form both rungs that go free go free at 84 and 85 per cent. The sentence is true of the samples and false as a description of the rung, and the difference between those two is the whole reason for sweeping.
The general shape of the mistake
A design places samples, a change falls between two of them, and the change gets described by the samples’ own coordinates. That is the same error a position quoted in sampled steps is, in a different thread, on a different quantity.
Both times the sentence was defensible and both times it read as a measurement. The repair is the same in both: quote a bracket as a bracket, and say how wide the sample’s step is.
What the three sweeps cost, in order
Ten positions between 70 and 97 per cent, which found nothing because the whole stretch is already free. Ten between 61 and 70, which bracketed the change. Nine at the grid, which placed it.
Twenty-nine positions, a hundred and sixteen runs, about three minutes. The first ten were spent looking in the wrong place, which is what a search costs when the design that motivated it had reported a bracket as a position.
What would have to be true for this to be an artefact
Worth writing out, since the finding rests on one rung and one quantity. It would be an artefact if the placement rule had a tie somewhere near that rise — two candidate azimuths with nearly equal sums — and the sweep were watching the tie break one way and then the other.
That is not ruled out and it is not the same as the finding being wrong. A tie breaking is a real property of the rule at that rise, and it would explain the flat-step-flat shape better than anything else on offer. What it would change is the word: a slot losing a wall would become a placement changing its mind, which is a smaller claim.
Reading the sum itself at the two rises would settle it and has not been done.
What a reader should carry
That the fourth cell’s cost is flat, falls by a hundred and fifty-four degrees in one step, and is flat again — so free names a rise rather than labelling a bucket.
And that five quantities were read on both sides of that step and all five are identical, which is what turns a jump into a transition rather than into a suspicion about the lattice.
What the picture at the top shows
Six rows, each naming a quantity read at the two rises the change sits between. Five are shaded one way and say held; one is shaded the other and says moves.
The five are the two walls, the settled divergence, the block, which cells wreck, and the lags the pair cut keeps rigid. The sixth is how far the next organ moves, and it goes from 163.59 to 9.14 degrees.
The one line
The fourth cell’s cost is 163.59 degrees at every rise above 0.00998 and under 14 degrees at every rise below 0.00997, with nothing in between across twenty-nine positions — so the change is a transition and the word free names a rise.
Five quantities are identical on both sides of it, and the sixth — where one organ goes — changes sign as well as size, which is what rules out a folded angle rather than a placement.
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.
- The alternation is not a period — both name artefact, claim testing, honest limits, resolution, rise
- A band with nothing inside it — both name claim testing, honest limits, resolution, rise
- A list that was a rounding — both name artefact, claim testing, honest limits, resolution
- A window nobody aligned — both name artefact, claim testing, honest limits, resolution
- An onset at the end of the run — both name artefact, claim testing, honest limits, resolution
- Every rise of a band — both name claim testing, honest limits, resolution, rise
Named objects
A flat tag is an object no other essay names yet.
ArtefactAzimuth gridBoth wallsClaim testingDisplacementHonest limitsInteractionResolutionRiseSlotThresholdTransition