RESULT 51: codex审计入册(门AND逃生孔=主因,600步连续放行×392;AIMD算术无罪;4臂回放对照r0 vs r868;修复×4已提交)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014FAPDWQ49M5Ye3NpTndTpn

1 files changed, 21 insertions, 0 deletions

diff --git a/docs/campaign/CASCADE_ABLATION_PLAN.md b/docs/campaign/CASCADE_ABLATION_PLAN.md
index 4ee3dbb..a15cc04 100644
--- a/docs/campaign/CASCADE_ABLATION_PLAN.md
+++ b/docs/campaign/CASCADE_ABLATION_PLAN.md
@@ -568,6 +568,27 @@ direction), not training-under-fault; wave-2 = co-training with faults injected
 
 
 
+### RESULT 51 (2026-07-19): CODEX AUDIT — the fw72m_simple collapse was a LEGALITY-GATE CODE
+DEFECT (user's "it's a bug" verdict CORRECT); my AIMD-equilibrium theory demoted to amplifier.
+Independent codex audit + 4-arm replay adjudication. THE HOLE: _legal's res/rho clause used
+AND (res>0.02 AND rho>0.9) — "res huge but rho<0.9" (large-displacement CONVERGING relax, the
+big-beta mode) passed as legal: 35.4k-36k = 600 CONSECUTIVE first-try-legal verdicts while
+beta climbed x392 (=1.01^600 exactly) into damaging gradients (cos 0.999->0.9556->0.90).
+Plus: res/rho used rank-0 bcast while drift used global max (rank-1 crossings committed);
+NaN compares silently legal; kretry rescue didn't persist halvings (upward bias, 0% causal
+here); up-step fired before gn/second-drift guards; bsimp not checkpointed.
+AIMD arithmetic EXONERATED with exact numbers: 4k-34k halving rate 0.01423/step ~= ln(1.01)/
+ln(2)=0.01436 equilibrium. 4-ARM REPLAY (s35000, 400 steps): plain2-lineage control @3e-3 =
+r0 zero events cos 0.9989; simple-lineage @3e-3 = r868 storm (its ceiling had sunk to ~1e-3,
+sigma 268 vs plain2's 242 — chronic boundary-riding damage is REAL as the amplifier);
+@9e-2 = d207, cos 0.569, K->8. Crown-3 shared the same contract failure (cos -0.21, drift
+0.067, zero skips). FIXES APPLIED (commit): OR-gate + NaN-illegal + ddp_max; kretry persist;
+up-step at commit point; bsimp in ckpt. Consequence: future endgame runs will reject on
+res>0.02 alone (stricter, fail-visible). fw72m_plain2 crown resumed s95000 on the OLD gate
+(safe: its fixed 3e-3 never enters the res-huge/rho-low hole; its risk class res>0.02 AND
+rho>0.9 was provably caught, wsync-arm r10/r21@190.3k). simple-v2 (fixed gate) ready for a
+clean-state validation arm pending user go.
+
 ### RESULT 50 (2026-07-18): c190 SEALED 3.3732 — centered rescues the plain-lineage state
 through the full death window (beta pinned 3e-3, min graze 2.54e-3, zero skips). 2x2 complete:
 the disease is NOT baked into the s190000 weights; single-sided CONTINUED updates collapse the