This branch formalizes which invariants are exact, which are branch-limited quantitative diagnostics, and which collapse to existing core logic. It also develops augmentation-deficiency structure used for repair planning.
The stable core remains fiber/factorization and row-space/kernel compatibility. Additive value currently comes from context and augmentation quantities (CID, delta_free, delta_C) and descriptor-lift diagnostics (DFMI, IDELB, CL) on supported families.
Canonical references are docs/methods-diagnostics/invariant-lane/invariant_formal_audit.md, invariant_theorem_spine_draft.md, invariant_no_go_spine_draft.md, and invariant_formalization_and_bh_placement_master_report.md.
This branch is intentionally theorem-first and overlap-aware: if a candidate invariant is only renamed row-space/fiber logic, it is demoted.