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166, 203, 218, 269 ] } }, "provenance": { "authors": [ "Lee, Gideon" ], "construction": "Two-block group-algebra code C(a,b) of arXiv:2610.13880 (Table 2) over the cyclic group C140 (GAP SmallGroup(140,4)): H_X = (L(a) | R(b)), H_Z = (R(b)^T | L(a)^T) with L and R the left and right regular representations, a = 1 + x^50 + x^101, b = 1 + x^133 in a generator x of order 140, i.e. the generalized bicycle code with A = a(x), B = b(x). The stored matrices use the qubit ordering of the paper's database (record 1cc3b2c654065790, github.com/gideonlsx/bicycle-race @ aed705a, data/codes.jsonl, CC BY 4.0): qubits 0..139 are the left block and 140..279 the right block, group elements numbered as GAP's Elements(SmallGroup(140,4)) with e0 the identity, x = e14, so a = e0 + e12 + e46, b = e0 + e25. Rebuilt from the database's group data; CSS commutation, k, check weight and both of the paper's witnesses were re-checked on the rebuilt matrices.", "origin": "baseline", "date": "2026-10-12", "model": "Claude Fable 5.1 (Claude Code)", "notes": "Literature reconstruction. The paper states d = 15 exactly (d_X: ladder in the screen (frontier mode, exact_on_accept; cluster engine, symmetry roots); d_Z: ladder in the screen (frontier mode, exact_on_accept; cluster engine, symmetry roots); verification record: one engine). Readings here: qldpc submit's RIS (20,000 NumPy trials per side) and its 2,000,000-trial accelerator pass, plus the verifier's refutation search; witnessed upper bound, see notes/280-6-15.md.", "novelty": "known_parameters", "references": [ "arXiv:2610.13880" ] }, "family": "generalized-bicycle" }