Derivative Calculator (symbolic + numeric) qualification

Ledger verdict

Verified with errata that must be applied at binding time.

Status

VERIFIED_WITH_ERRATA

Tranche

tranche-8

Review vectors

4

Ledger rows

1

Applied errata

[
  {
    "vector": 1,
    "field": "spot_checks[0] (at x=0)",
    "wrong": "input_side=-0.9999999999",
    "correct": "-1.9999999999 (matches answer_side=-2.0 to 10 decimals)",
    "cause": "the numeric finite-difference at x=0 is off by almost exactly a factor of 2 from the correct derivative — consistent with dividing by h instead of 2h in the central-difference formula; the SAME vector's x=1 spot-check is computed correctly, so the error is local to this one point, not the whole method"
  }
]

Adversarial re-test context

The full catalog was re-tested from boundary, convention, and self-check angles in 2,787 requests. Five genuine computational defects were independently verified and corrected. This page reports the current ledger state for this instrument; it does not imply product deployment or interface qualification.

Release gate

Bind every attached correction, replay the affected vectors, enforce boundary validation, and preserve evidence before describing the executable surface as qualified.

Other records

Sources and evidence

These pointers bind the page to evidence. They do not grant authority or collapse verification into deployment.

• VERIFIED_LEDGER.json
• STRESS_TEST_RECEIPT.json
• tranche errata record