{
  "tm": "1RB0RD_0LC0RA_1LA1LC_1RE0LF_0RA1RF_1LB---",
  "label": "W7-5",
  "status": "CHECKPOINT_B",
  "stage": "informal_proof",
  "updated": "2026-10-14",
  "confidence": "high",
  "holdout_line_740": 274,
  "reason": "Checkpoint B review: sound, 5 minor gaps, all fixed (proof.md section 11): S0 sentence corrected; O2 field law derived in 4.3 (gap rule g_1-1, g_2..g_(m-1), g_m-1, or g_1-2 if m=1); r' = rest of r + 2 covers RA2/RA3/L5e; 5.2 (D2) split into m>=2 / m=1; notes.md 514 counts corrected. proof.md (start-parametric, lines 274 and 514): 14 pass lemmas (S0, L1-L7, RA1-RA3, RE1-RE2) proved for all exponents by symbolic execution from six shift rules; the sweep is their composition, exact against the machine on 80k in-domain configurations; invariant B(k;f) with f_(k-1) >= (4^k-4)/3, epoch theorem B(k) -> B(k+1) in 2*4^k-3 sweeps with newborn field 3*4^k-5 (or -6) >= (4^(k+1)-4)/3; openings 274 blank -> B(3; 0,41) at step 7,910, 514 (start F mirrored, phi) -> B(2; 7) at step 792. check_proof.py: 82 checks, 0 failures, ~7 s. Not a kill until tools/check_kill.sh PASS.",
  "siblings": [
    "1RB---_0RC0LD_1RD1RC_1LB0LE_1LF0RA_0LD1LA"
  ],
  "sibling_note": "Line 514 is start F of the same table, mirrored. It enters the same language at step 792 (274 at step 108) and then follows the same rules with the same counter value; only one field differs (+4 words), and that offset moves into the next field whenever the cluster absorbs a digit. One closed-language proof plus two entry lemmas covers both lines.",
  "upstream": "No upstream proof of either start. verify/Sk1Machines.v (mxdys) Sk1Counter/Sk1CounterMixed applies only partly: same digit-counter shape, but wraps move a digit 2 cells (re-cut), consumption reaches through empty fields (outside its batch rule), and O2's E-pass/birth is a second kind of visit; proof.md 9.1.",
  "next_goal": "Formalize (proof.md section 9.2): shift rules + pass lemmas in Individual62 style, abstract sweep with domain option, epoch invariant by induction on t (lia/nia), openings by solve_init (274: 7,910 steps) and flip_halts/perm_halts + 792 steps (514).",
  "formal": {
    "file": "1RB0RD_0LC0RA_1LA1LC_1RE0LF_0RA1RF_1LB---.v",
    "sha256": "1dec277e5a7d867f...",
    "check_kill": [
      "PASS formalizer round 1 2026-10-14 23:03 (rocq/check_kill_r1.txt, coqchk pass)",
      "PASS orchestrator 2026-10-14 (rocq/check_kill_orchestrator.txt)"
    ],
    "pending": "independent audit agent, then status KILLED_NONHALT + submission bundle; line 514 needs its own delta file (rocq/log.md, Open)"
  }
}