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 "provenance": {
  "authors": [
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  "construction": "Triangular 4.8.8 (square-octagon) color code at distance 7, reproduced from arXiv:2609.21376 Appendix D: data qubits on a triangular region of the square lattice (row widths 3,5,7,7,5,3,1), square weight-4 and octagon weight-8 faces, each face carrying both an XX and a ZZ check; H_X = H_Z = face-incidence matrix.",
  "origin": "submission",
  "date": "2026-09-21",
  "model": "GLM 5.3 Flash",
  "notes": "Reproduction of the published triangular 4.8.8 color code family (arXiv:2609.21376v1, Appendix D); parameters known in the literature. Checked against the board: no exact or WL-equivalent match to an existing entry. The paper proves circuit distance d_circ = d at d = 7 under superdense extraction; the code distance here is a witness-backed upper bound. Circuit tier (Shutty's superdense 12-CNOT-layer extraction adapted to the board recipe) added 2026-09-22, PR #1770; see circuit.notes and fieldnotes/2026-09-22-shutty-488-circuit-adapter.md."
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  "notes": "Superdense 12-CNOT-layer extraction of Shutty, 'Denser Planar Color Codes' (arXiv:2609.21376), starting phase 0 with forward/backward cycle alternation, 33 ancillas (64 qubits total), 7 cycles. Reproduced from the noiseless CNOT circuits planar_488_d7_r7_{X,Z}_phase0.stim in the Zenodo bundle 10.5281/zenodo.22820614 (Apache-2.0); gates and layers unchanged. Two convention adaptations: (1) X memory prepares/reads data with RX/MX in place of R;H / H;M; (2) the bundle's observable carries Pauli-frame ancilla records, so it is re-expressed on the final readout alone by XORing in the detector combination that cancels them (same logical class in the DEM, so d_circ is unaffected); the result is the transversal all-31 logical. Noise is the board recipe, not the paper's SI1000/native-CZ model. Witnesses are seven final-readout flips along a weight-7 logical.",
  "contributed_by": {
   "by": [
    "@FarLab"
   ],
   "date": "2026-09-21",
   "method": "adapter over the published circuits; GF(2) elimination for the observable; witness constructed, RIS on ker(H_dem) (1e7-trial cap, 240 s per basis) found nothing below 8; Claude Fable 5.1"
  }
 }
}