# Construction data for arXiv:2606.27130

This directory contains construction data for the rate-2/3 girth-8 (3,18)-regular CSS LDPC code in arXiv:2606.27130.

Main files:

- `rate23_qldpc_2606_27130_summary.json`: compact summary of parameters, finite-field base data, lift constraints, and verification results.
- `rate23_qldpc_2606_27130_code.json`: full public construction record, including affine CPM coefficients and expanded base-edge shifts.
- `rate23_qldpc_2606_27130_ansatz_coefficients.{csv,json}`: the 108 affine CPM shift coefficients.
- `rate23_qldpc_2606_27130_edge_shifts.{csv,json}`: the 2052 CPM shifts for all nonzero base edges.
- `rate23_qldpc_2606_27130_lift_coefficients.html`: human-readable coefficient tables.
- `observed_logical_supports.{csv,json}`: low-weight logical supports observed during the iterative construction procedure, rewritten with neutral public identifiers.
- `forbidden_base_supports_affine_orbit.{csv,json}`: the 285 forbidden base supports after projection and affine-orbit expansion.
- `explicit_girth_verification.json`: row/column weight, orthogonality, and same-type girth verification summary.
- `forbidden_support_verification.json`: compatibility check summary for the forbidden supports.
- `Hx_rows.json`, `Hz_rows.json`: expanded row-support representation of the lifted binary matrices.
- `weight310_logical_structure_search.json`: structure summary for the weight-310 logical upper-bound witness.

Indexing convention:

A lifted column is `P * base_col + sheet`, where `P = 101` and `0 <= sheet < 101`. In the edge-shift table, a base edge `(row, col)` with shift `s` gives lifted row `101 * row + r` a nonzero at lifted column `101 * col + ((r + s) mod 101)`.