mathlib-fp 1.9.9 release notes

Version 1.9.9 is the final 1.9.x convergence release. It introduces no planned public capability. It closes the evidence, compatibility decisions, and exact manifest of additive public work assigned to 1.10.0, and is the handoff to the minor release that completes the approved API before the final 2.0 freeze.

Closed 1.10.0 capability manifest

The machine-readable capability-manifest-1.10.0.json and its human-readable explanation close every accepted capability gap:

• TVector2D.Rotate(const Angle: Double): TVector2D is declared for 1.10.0 only, with a complete behavior contract (radians, counter-clockwise positive, allocation-free value operation, source immutability, Perpendicular agreement at π/2, magnitude tolerance, zero-vector, and non-finite behavior), a test plan, a documentation plan, and an empty compatibility impact.
• The deprecation-marking decision closes as no-deprecation: the 1.9.7 rehearsal decisions stand, all 21 aliases remain retained, and full 1.x source compatibility is retained throughout 1.10.0.
• Every other proposal — 3-D rotation, advanced spectral/sparse/iterative/DSP families, conditional statistics, general persistence, parallelism, and any new domain — is explicitly deferred beyond 2.0 with a recorded reason.

tools/check_convergence.py enforces the manifest against the roadmap, the 1.9.3 API decision, the 1.9.7 rehearsal, the capability inventory, and the frozen 1.9 API snapshot on every change.

Final candidate API snapshot and diff

The final snapshot and exact diff confirm the compiled 1.9.0-to-1.9.9 diff is empty across source, behavior, warnings, and packaging. The candidate 2.0 surface is exactly the frozen 1.9 snapshot plus the closed 1.10.0 additions.

Provenance and governance

• The provenance audit covers every stable src/ unit: algorithm provenance, fixture provenance, MIT licence status, and the no-third-party-code/no-runtime-dependency guarantees.
• The governance policies complete the 2.x maintenance policy, support policy, deprecation policy, contribution gate for new domains, and security support window. SECURITY.md and CONTRIBUTING.md carry the user-facing statements.

Upgrade notes

• Existing 1.9 code requires no edit; the public 1.9 interface remains frozen.
• 1.9.9 adds no declaration, no warning, no behavior change, and no package change.
• The closed manifest is a declaration for 1.10.0; 1.9.x does not implement it.

Qualification boundary

Local evidence is recorded in QUALIFICATION_1.9.9.md. Exact Linux and Windows checksummed, network-isolated clean-archive candidate jobs remain mandatory before tagging; no local result is generalized to a target that did not run.

Known limitations

• 1.10.0 and 2.0.0 remain future releases; the 1.9.x line ends with this release.
• Deferred families remain visible as unsupported in the capability inventory until a future design activates them.