tools/rebuild_pages.sh rebuilds the site within 5 minutes of a change; by hand: python3 -B tools/site.py.1RB0LC_0RC0RF_1RD0RE_1LE0RA_0LA0LE_1LD---
Where it stands
Parked at the observation
Twin port fails (directions.md section 1, critic's caveat realised). Each B1 exit is the 4-cell event A> 0100 -> D0011101 -> next exit, its self-sustaining exit chain) and this machine gets D0011_011001 (-> D00101001 merge, no exit).
Read the full status
That first happens at the 6th exit (Inc 528728, read at Inc 528977, >= 1.0e11 steps); from there the Inc orbits never meet again. TM3 reaches upstream's cycle base S' at Inc 1333832; this machine never has the S' prefix (to 3e6 Inc) and S' is not a cycle for it (from S'(r) its Inc reads r after 777 steps). No delta proof exists; nonhalting needs an invariant of the modified digit system (direction 2, K42).
About this picture
The standard picture (bbchallenge.org's Default view): each row is the whole tape at one step, time runs downward, and the head's path draws the pattern.
Overview
In one sentence
same state names, same start A, no mirror; differs only in B1 (TM3 1RF, here 0RF) and F0 (TM3 1RD, here 1LD) (status.json relation)
- Status
- Parkedtwin port · updated 2026-10-14Not blocking · Stuck at the twin port stage.idle since Oct 14 16:24 (45 h ago) · status.json 2026-10-14
- Class
- Skelet 1-like Class 1
- On the list
- line 112 of
BB6_holdouts_663.txt· historical 740 line 124
Your calls on file 1
- next
- Hand the Coq-checked model to direction 2 (K42 F-entry atlas): it is the exact digit-level simulator that direction asks for, for this line. Not a direction-1 target any more.
Mechanism
Proof & checks
No proof work yet.
Files
machines/<tm>/: 3 entries · raw notes, status, scripts, images
| name | size | changed |
|---|---|---|
| notes.md ↓ | 7.2 KB | 2026-10-14 16:14 |
| status.json ↓ | 2.3 KB | 2026-10-14 16:10 |
| scripts/ | 4 items | 2026-10-14 16:12 |
status.json in full
{
"tm": "1RB0LC_0RC0RF_1RD0RE_1LE0RA_0LA0LE_1LD---",
"label": "P-124",
"status": "STUCK",
"stage": "twin_port",
"updated": "2026-10-14",
"confidence": "high",
"holdout_line_740": 124,
"holdout_line_778": 131,
"class": "Skelet 1-like Class 1 (K42 core)",
"upstream_twin": "Sk1like_TC_v1.v Module TM3 = 1RB0LC_0RC1RF_1RD0RE_1LE0RA_0LA0LE_1RD--- (nonhalt)",
"relation": "same state names, same start A, no mirror; differs only in B1 (TM3 1RF, here 0RF) and F0 (TM3 1RD, here 1LD)",
"reason": "Twin port fails (directions.md section 1, critic's caveat realised). Each B1 exit is the 4-cell event A> 0100 -> <E 0001 (TM3, 7 steps) / <E 0110 (here, 5 steps), so in upstream's digit model this machine writes D0011001 where TM3 writes D0000101 (or D00001 0 + D01). Read again as a leading digit, both become D001101 (bounded-delay reconvergence: exits 1-5, +12 steps each, the 3e8 evidence). Read as the second digit after D0011 0, TM3 gets D0011_000101 (-> D0011101 -> next exit, its self-sustaining exit chain) and this machine gets D0011_011001 (-> D00101001 merge, no exit). That first happens at the 6th exit (Inc 528728, read at Inc 528977, >= 1.0e11 steps); from there the Inc orbits never meet again. TM3 reaches upstream's cycle base S' at Inc 1333832; this machine never has the S' prefix (to 3e6 Inc) and S' is not a cycle for it (from S'(r) its Inc reads r after 777 steps). No delta proof exists; nonhalting needs an invariant of the modified digit system (direction 2, K42).",
"result": "exact digit-level model RInc2/Inc2 (upstream RInc with 3 exit branches changed + one new return kind Tp3 = <E 011001 w^n); RInc_spec, Inc_spec and init for this machine compile with coqc 8.20 against the pinned framework in 11 s (scripts/P124_model.v; model lemmas only, not a kill). Inc2 orbit to 1e9 Inc: no inr, no cycle signature, 11 exits.",
"evidence": "scripts/twin_check.py (all checks PASS; output in scripts/twin_check.out)",
"next": "Hand the Coq-checked model to direction 2 (K42 F-entry atlas): it is the exact digit-level simulator that direction asks for, for this line. Not a direction-1 target any more.",
"pair": "740 line 64 (P-64, mirror twin of TM1 = the same upstream table started in D): its exit (in TM3 names B1 = 0RF, F0 = 1RD) returns in state C instead of E, so it needs its own Inc-level comparison; expect the same kind of break."
}