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 "provenance": {
  "authors": [
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  "construction": "multi-band dense-packed surface code, rows=2 m=2 pitch=4 (raised-pitch generalization of arXiv:2511.06758)",
  "references": [],
  "date": "2026-09-01",
  "notes": "",
  "model": "GLM 5.3 Flash",
  "origin": "submission"
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  "notes": "Generic sequential two-block extraction: one ancilla per check, X checks then Z checks each round with joint reset/measure layers; CX layers are a proper edge coloring of each Tanner graph (4 X + 4 Z CX layers per round, schedule seed 0; hook-aware orders: every CNOT order suffix needs >= d-1 further data errors to complete a logical, layered by min-conflicts search). Screened by RIS on ker(H_dem) and an observable-constrained seeded BP+OSD search; witnesses validated in GF(2).",
  "contributed_by": {
   "by": [
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   "date": "2026-09-16",
   "method": "generic CSS memory schedule: one ancilla per check, CX layers from a bipartite edge coloring, CNOT orders filtered by a hook-error criterion; screened by RIS on ker(H_dem) and an observable-constrained seeded BP+OSD search"
  }
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}