BB(6) hunt
Machines / #13

1RB0LE_1LC1RD_1LA0RB_1RC1RB_1LF0LC_---0RC

#13ParkedBouncer + Chaotic Edgebbchallenge ↗Explorer

Where it stands

Parked at the informal proof

Parked by Dennis 2026-10-10 (decision queue: park; proof.md kept as the conditional reduction). Fatal skeptic gap stands: the edge lemma is unproved, so non-halting is only conditional.

Read the full status

(E) as first stated just restates 'the edge never breaks'. proof.md now sharpens it to (E'): a one-sided right-part system with a fixed 16-round-trip protocol at the boundary one cell left of the X0|D cut (checks IFACE, E'). No closed language L is known, and none of the regular candidates closes: SFT_k invariants are refuted for k <= 36 (verified chains in work/sft_refutations), and plain n-gram CPS does not close, whole-machine n <= 26 or edge-system n <= 24. Whether any regular invariant exists is unknown. Everything else (rules, bounces, cycle law, init at 784,041 via the Bouncer_v3 pattern) is routine and checked. Minor gaps 2-7 fixed (review log in proof.md section 9). PRIORITY CALL for Dennis: spend more budget on (E')? Routes: native reimplementation of busycoq CTL modes for a whole-machine certificate (days, unknown odds), or edge-only closed set plus a new Coq checker (1-3 weeks plus finding the set).

Observe
Deepen
Informal proof
Rocq
space-time diagram, first 10,000 steps from blank
The first 10,000 steps from a blank tape. Time runs down; white is 1.
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.

bbchallenge-defaultStart blankRows steps 0 → 10,000, top to bottomWindow cells −200..199, left to rightColors 1 0 or unvisited

Overview

In one sentence

Clean period-10 bouncer; every 7 bounces a fixed probe stirs a ~144-564-cell chaotic tail D. Tail = the whole problem.

Status
Parkedinformal proof · updated 2026-10-10Not blocking · Stuck at the informal proof stage. Answer Q1–Q3 whenever; a “no” redirects the work.
idle since Oct 10 12:52 · status.json 2026-10-10
Informal proof
proof.mdconditional; see Proof for what is still open
Class
Bouncer + Chaotic Edgeours: Bouncer + Chaotic Edge (sheet) · ours adds: translating period-10 bouncer feeding a 1-sided chaotic edge map · high confidence
On the list
line 401 of BB6_holdouts_663.txt · historical 740 line 443
#13eqv ×1table ×3sim 1e15UBRRBA
Your calls on file 3
priority call (answered)
Continue investing in the edge lemma (E') or park the machine?
parked
Parked by Dennis 2026-10-10 (decision queue: park; proof.md kept as the conditional reduction).
decision.json · answered 2026-10-10: park
Continue investing in the edge lemma (E') or park the machine? Decisions →

Mechanism

How it works: 3 notes
  • Bulk (1101101101)^a sits on a left wall; each bounce shifts it 1 cell left (70a steps).
  • A fixed 54-cell junction cycles through 7 shapes; the bulk gains 1 block per 7 bounces.
  • Only every 7th bounce enters the tail D (the same 16 round trips = 32 crossings, one cell left of the cut, each time). D stays 144-564 cells, content chaotic.

Figures for Checkpoint A

Fig 1 · One row per bounce, from a built tapeQ1viewer ↗

One row per bounce from a built tape: bulk at left, junction seam in the middle, tail D at right.

One row per bounce, from a built tape
bbchallenge-defaultStart constructed: 0∞ <A (1101101101)20 X0 D0 0∞Rows left recordsWindow cells -320..725, 1 px = 0.5 cellsColors 1 0 or never visited head just moved right/left
Start: X0 = the fixed 54-cell junction; D0 = the real 261-cell tail at step 784,041, where the real bulk is a = 59, not 20 · Rows: the start, then one row per new leftmost cell = one row per bounce (321 rows, steps 0..1,200,000; 7 rows = one probe cycle) · Window: each cell is 2x2 px; cell 0 = the cell the head reads at the start
Fig 2 · Right end only, 100 million stepsQ2viewer ↗

Each row is shifted so the right edge stays put. Compare the noisy band's width at top and bottom.

Right end only, 100 million steps
bbchallenge-defaultStart blankRows left recordsWindow cells -1199..0, 1 px = 1 cellColors 1 0 or never visited head just moved right/left
Rows: the start, then one row per new leftmost cell = one row per bounce (4,297 rows, steps 0..100,000,000; rows are not equal time) · Window: counted from the right edge (each row is shifted so its rightmost visited cell is at 0; the bulk continues off-picture to the left)
Fig 3 · Blaze view, 10 million stepsQ3viewer ↗

Blaze view to 1e7 steps. Compare the left edge with the right edge.

Blaze view, 10 million steps
bbchallenge-blazeStart blankRows Blaze time blocks of 16,384 stepsWindow cells -1256..1085, 1 px = 2.93 cellsColors 0 1 mixed
Rows: (averaged), 611 blocks stretched to 500 px, so 1 px row ~ 20,000 steps (steps 0..10,000,000) · Colors: paler orange: each pixel averages its cells over its time block; no head drawn
More figures (1)Fig 4: bbchallenge Default view, first 10,000 steps
Fig 4 · bbchallenge Default view, first 10,000 stepsviewer ↗

For orientation: the start of the run as bbchallenge.org shows it.

bbchallenge Default view, first 10,000 steps
bbchallenge-defaultStart blankRows every step 0..10,000Window cells -200..199, 1 px = 1 cellColors 1 0 or never visited head just moved right/left
Rows: squeezed 20:1 into 500 px as on bbchallenge.org (px row y blends steps 20y+9 and 20y+10)
Rules (8/8 validated)exact tape rewrites the proof will formalize, each re-checked by simulation
rulefrom ⟶ tocasesstepschecked
cycle (7 bounces)
0∞ <A (1101101101)a X0 D 0∞
⟶ 0∞ <A (1101101101)a+1 X0 P(D) 0∞
P(D) chaotic; holds every cycle from step 784,041 (a=59)490a + O(|D|^2)✓1951/1951
probe bounce
0∞ <A (1101101101)a X0 D 0∞
⟶ 0∞ <A (1101101101)a X1 011 P(D) 0∞
P independent of a; fixed 16 round trips (32 crossings) one cell left of the cut70a + c(D), c in [2235,10775]✓180/180
junction bounces k=1..5
0∞ <A (1101101101)a X_k D 0∞
⟶ 0∞ <A (1101101101)a+[k=5] X_(k+1) D 0∞
D untouched (any D); X_k in notes.md70a+b_k, b=(9,473,55,49,77)✓80/80
cycle close k=6
0∞ <A (1101101101)a X6 011 D 0∞
⟶ 0∞ <A (1101101101)a X0 D 0∞
cut moves +3 cells70a+9✓16/16
right sweep
1 B> (0110110111)n
⟶ (0111101101)n 1 B>
—12n✓16/16
left sweep
(1011110110)n 11110101 <E 0
⟶ 11110101 <E 0 (1101101101)n
—58n✓16/16
left wall
0∞ <A r
⟶ 0∞ 1 B> r
—1✓30/30
halt pattern
001 C> 0
⟶ halt
the only halting route4✓20/20
Compressed historythe tape as 0∞ <A (1101101101)a X0 D 0∞ (X0 = 110111100110011101100100100111101100100110110111010011) at 33 moments: where the rules are read off
0∞ <A (1101101101)a X0 D 0∞ (X0 = 110111100110011101100100100111101100100110110111010011)
stepa|D|D (first 24 cells)
784,041592611.1·1022
819,860602581.1·1022
852,629612551.11·1022
889,610622521·1021
924,145632491.1·1022
960,508642461.11·1022
996,135652431·1021
1,141,833692311.1·1022
1,259,438722221·1021
1,462,875772071.11·1022
1,730,709832491.1·1022
2,116,305912551.11·1022
2,638,4891012851.11·1022
3,459,8631153631.11·1022
4,721,1161343361.1·1022
6,636,6751593211.11·1022
9,643,1281923121.1·1022
14,607,1612373271.1·1022
22,589,5842963001·1021
35,992,4893753631.1·1022
58,743,1034812851.11·1022
97,252,2276212551.1·1022
164,063,0198093211.1·1022
279,751,4651,0594111·1021
482,122,7051,3932791.11·1022
835,786,6571,8373871·1021
999,751,7422,0103481.1·1022
2.45·10141,000,059261edge map (|D| 144-519 in window)
9.8·10142,000,059321edge map (|D| 180-561 in window)
2.2·10153,000,059261edge map (|D| 171-534 in window)
3.92·10154,000,059381edge map (|D| 183-564 in window)
6.12·10155,000,059291edge map (|D| 174-519 in window)
7.41·10155,500,059321edge map (|D| 171-552 in window)
alast 5,500,059
5.5e6597.8e57.4e15log-logstep 784041: a = 59step 819860: a = 60step 852629: a = 61step 889610: a = 62step 924145: a = 63step 960508: a = 64step 996135: a = 65step 1141833: a = 69step 1259438: a = 72step 1462875: a = 77step 1730709: a = 83step 2116305: a = 91step 2638489: a = 101step 3459863: a = 115step 4721116: a = 134step 6636675: a = 159step 9643128: a = 192step 14607161: a = 237step 22589584: a = 296step 35992489: a = 375step 58743103: a = 481step 97252227: a = 621step 164063019: a = 809step 279751465: a = 1059step 482122705: a = 1393step 835786657: a = 1837step 999751742: a = 2010step 245034037373157: a = 1000059step 980068074502653: a = 2000059step 2205102110427991: a = 3000059step 3920136152881851: a = 4000059step 6125170190818191: a = 5000059step 7411437208047181: a = 5500059
|D|last 321
4112077.8e57.4e15log xstep 784041: |D| = 261step 819860: |D| = 258step 852629: |D| = 255step 889610: |D| = 252step 924145: |D| = 249step 960508: |D| = 246step 996135: |D| = 243step 1141833: |D| = 231step 1259438: |D| = 222step 1462875: |D| = 207step 1730709: |D| = 249step 2116305: |D| = 255step 2638489: |D| = 285step 3459863: |D| = 363step 4721116: |D| = 336step 6636675: |D| = 321step 9643128: |D| = 312step 14607161: |D| = 327step 22589584: |D| = 300step 35992489: |D| = 363step 58743103: |D| = 285step 97252227: |D| = 255step 164063019: |D| = 321step 279751465: |D| = 411step 482122705: |D| = 279step 835786657: |D| = 387step 999751742: |D| = 348step 245034037373157: |D| = 261step 980068074502653: |D| = 321step 2205102110427991: |D| = 261step 3920136152881851: |D| = 381step 6125170190818191: |D| = 291step 7411437208047181: |D| = 321
D (first 24 cells)last edge map (|D| 171-552 in window)
1.1e221e217.8e51e9log xstep 784041: D (first 24 cells) = 11001001101101100100110step 819860: D (first 24 cells) = 11001001001100100100110step 852629: D (first 24 cells) = 11101101100100110011011step 889610: D (first 24 cells) = 1001001100100110110010step 924145: D (first 24 cells) = 11001001100100100110111step 960508: D (first 24 cells) = 11101101100100111011011step 996135: D (first 24 cells) = 1001001100100110110010step 1141833: D (first 24 cells) = 11001001101101110100110step 1259438: D (first 24 cells) = 1001001100100110110010step 1462875: D (first 24 cells) = 11101101100100111011011step 1730709: D (first 24 cells) = 11001001100100100110111step 2116305: D (first 24 cells) = 11101101100100111011011step 2638489: D (first 24 cells) = 11101101100100111011011step 3459863: D (first 24 cells) = 11101101100100111011011step 4721116: D (first 24 cells) = 11001001100100100110110step 6636675: D (first 24 cells) = 11101101100100111011011step 9643128: D (first 24 cells) = 11001001001100100100110step 14607161: D (first 24 cells) = 11001001101101110100110step 22589584: D (first 24 cells) = 1001001100100110110010step 35992489: D (first 24 cells) = 11001001100100100110110step 58743103: D (first 24 cells) = 11101101100100111011011step 97252227: D (first 24 cells) = 11001001001100100100110step 164063019: D (first 24 cells) = 11001001100100100110111step 279751465: D (first 24 cells) = 1001001100100110110010step 482122705: D (first 24 cells) = 11101101100100111011011step 835786657: D (first 24 cells) = 1001001100100110110010step 999751742: D (first 24 cells) = 11001001100100100110111
Template comparisonBouncer_v3.v TM1: partly applies · the nearest solved proof, what carries over, and the transitions that differ
01
A1RB0LE
B1LC1RD
C1LA0RB
D1RC1RB
E1LF0LC
F---0RC

differs from the template

file
Bouncer_v3.v:44
module
TM1
machine
1LB1RA_0RA0RC_---1RD_1RE1RB_1LF0LE_0RD0LE (10 transitions apart)
diff
8 transitions apart under best relabel (A0 A1 B0 B1 C0 C1 E0 F1): class template, not a neighbour
note
Shape carries over: left wall (sideRLs_wall) + whole tape as right side + k-bounce BigStep (ours k=7, theirs 128). Its RInc native check needs a periodic edge; our D never repeats (5500000 cycles), so D needs a closed-language lemma.
Proof strategy & riskshow the formal proof will go · 3 risks to watch

Longitudinal split as in Bouncer_v3/LongNv1: wall + bulk sweeps by ind (12n, 58n) + 7 fixed junction bounces reduce nonhalt to the 1-sided edge map D -> P(D) with a fixed 16-round-trip (32-crossing) input one cell left of the cut (sideRLs list). Then find a closed regular language for D outside Rocq (CTL/FAR-style automaton on the edge map) and check it in Rocq verified-checker style (Fixpoint + soundness + vm_compute).

  • ▲No small closed language for D may exist (FAR failed on the full machine; the SFT {000,0101,01101111} is not closed).
  • ▲Proving P independent of a and the junction lemmas needs segRLs/sideRLs plumbing (LongN/InfiniteRect style, 15-30 KB).
  • ▲|D| bounded only empirically (144-564); a very long transient could still end in 001 C> 0.
Stats & provenance109 steps simulated · 20,564 cells · the status in full · files
simulated
109 steps
tape
20,564 cells · 14,332 nonzeros
growth
both edges ~sqrt(t) (lo -0.44sqrt t, hi +0.21sqrt t); edge map 5500000 cycles ~ 7.4e+15 steps, |D| 144-564
status now
Parked by Dennis 2026-10-10 (decision queue: park; proof.md kept as the conditional reduction). Fatal skeptic gap stands: the edge lemma is unproved, so non-halting is only conditional. (E) as first stated just restates 'the edge never breaks'. proof.md now sharpens it to (E'): a one-sided right-part system with a fixed 16-round-trip protocol at the boundary one cell left of the X0|D cut (checks IFACE, E'). No closed language L is known, and none of the regular candidates closes: SFT_k invariants are refuted for k <= 36 (verified chains in work/sft_refutations), and plain n-gram CPS does not close, whole-machine n <= 26 or edge-system n <= 24. Whether any regular invariant exists is unknown. Everything else (rules, bounces, cycle law, init at 784,041 via the Bouncer_v3 pattern) is routine and checked. Minor gaps 2-7 fixed (review log in proof.md section 9). PRIORITY CALL for Dennis: spend more budget on (E')? Routes: native reimplementation of busycoq CTL modes for a whole-machine certificate (days, unknown odds), or edge-only closed set plus a new Coq checker (1-3 weeks plus finding the set). (status.json, 2026-10-10)
observer's note
Mechanism found and validated (bulk, junction, probe); tail D is chaotic but bounded, not arithmetic (no Collatz-like growth), so not a cryptid. Next: closed language for the edge map.
files
observe.json · notes.md · proof.md · status.json

Proof & checks

Files

machines/<tm>/: 9 entries · raw notes, status, scripts, images

namesizechanged
notes.md ↓8.9 KB2026-10-10 12:49
proof.md ↓24 KB2026-10-10 04:25
status.json ↓1.4 KB2026-10-10 12:52
observe.json ↓12 KB2026-10-10 04:41
decision.json ↓3.9 KB2026-10-10 12:49
img/10 items2026-10-10 02:00
scripts/7 items2026-10-10 04:25
work/19 items2026-10-10 04:20
check_proof.py ↓16 KB2026-10-10 04:24
status.json in full
{
 "tm": "1RB0LE_1LC1RD_1LA0RB_1RC1RB_1LF0LC_---0RC",
 "status": "STUCK",
 "stage": "informal_proof",
 "updated": "2026-10-10",
 "reason": "Parked by Dennis 2026-10-10 (decision queue: park; proof.md kept as the conditional reduction). Fatal skeptic gap stands: the edge lemma is unproved, so non-halting is only conditional. (E) as first stated just restates 'the edge never breaks'. proof.md now sharpens it to (E'): a one-sided right-part system with a fixed 16-round-trip protocol at the boundary one cell left of the X0|D cut (checks IFACE, E'). No closed language L is known, and none of the regular candidates closes: SFT_k invariants are refuted for k <= 36 (verified chains in work/sft_refutations), and plain n-gram CPS does not close, whole-machine n <= 26 or edge-system n <= 24. Whether any regular invariant exists is unknown. Everything else (rules, bounces, cycle law, init at 784,041 via the Bouncer_v3 pattern) is routine and checked. Minor gaps 2-7 fixed (review log in proof.md section 9). PRIORITY CALL for Dennis: spend more budget on (E')? Routes: native reimplementation of busycoq CTL modes for a whole-machine certificate (days, unknown odds), or edge-only closed set plus a new Coq checker (1-3 weeks plus finding the set).",
 "parked": "Parked by Dennis 2026-10-10 (decision queue: park; proof.md kept as the conditional reduction).",
 "priority_call_answered": "Continue investing in the edge lemma (E') or park the machine?"
}