math.factorial

Three distinct suites: educational examples on the calculator page, this legacy regression count (24/24 golden + boundary), and the CVP verification suite below. They are not the same number. Property, metamorphic, round-trip, O3, and interface statuses/checks are recorded in the CVP Manifest . SKIP (0/0) means that suite has no published vectors.

This calculator CURRENT · Public schema 1.0.4 matches · Semantic contract ✓ · Production attested · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-10-20.factorial-complete-contract-v3. Calculation version 1.0.4. CVP 1.0.0-proposed. 6/6 golden · 7/7 CVP boundary · 6/6 invalid · 19/19 property · 5/5 metamorphic · 23/23 O3 · 1/1 cross-interface · 6/6 CVP contract. digest 9ad5f31d8553. Exact decimal-string identity vs Python math.factorial on the 23 published tabulated vectors (named 0,1,5,10,20,100,5000 plus 16 seeded n in 0–4999). 5000! is verified as the full 16,326-digit value and as SHA-256 of those ASCII digits. This is not a whole-domain proof beyond the published table.

• Golden (oracle-backed) 6 / 6
• CVP boundary 7 / 7
• Invalid input 6 / 6
• Property 19 / 19
• Metamorphic 5 / 5
• O3 independent oracle 23 / 23
• Cross-interface 1 / 1
• CVP contract 6 / 6
• Interfaces PASS · UI (SSR) / REST / MCP
• Interface claim ui-ssr is query-result HTML, not a live browser session.
• Assurance Core

• release artifacts aligned PASS
• schema output required declared PASS
• schema valid input executes PASS
• engine success output validates schema PASS
• schema rejects incomplete input PASS
• rest success payload validates schema PASS

Fingerprint sha256:af9f396fcf6579934d52a37116e2049d5dc0d2117adb2b97c8f46b655e744695

Input schema sha256:65b528e8230052d58f33f790dc9d8eed93e982757269a75f1db13264fce18347 · Output schema sha256:dc7e95b6f3e83892b07fd746ded7cf1981c8091b887c07dfaa9757fe1269ca40 · Build-time SHA-256 digests prove published artifacts agree with each other (release_integrity.scope=workspace). Production attestation GETs canonical URLs twice (public/cached view and origin), including Capability HTML, via npm run attest:production --write (published at /.well-known/calculatorx-production-attestation.json) and fails if the public Capability page advertises a different calculation_version. This is artifact consistency, not an independent immutable release log.

Tool

factorial

Engine

factorial

Engine build

2026-10-20

Evidence core

2026-10-20T10:40:00.133Z

Rendered

2026-10-23T01:27:11.446Z

Last reviewed

—

Assumptions

• n is an integer satisfying 0 ≤ n ≤ 5000.
• Ordinary (single) factorial only — not multifactorial and not the real Gamma function for non-integers.

Limitations

• Ordinary (single) factorial only — not multifactorial and not Γ(n+1) for non-integers
• Domain is 0 ≤ n ≤ 5000 (product/resource bound, not a mathematical bound)
• Missing n → MISSING_REQUIRED_INPUT
• Non-numeric or non-integer n → INVALID_NUMBER
• n < 0 → VALUE_MUST_BE_NON_NEGATIVE
• n > 5000 → VALUE_ABOVE_MAX
• Digits-only strings: trimmed length≤64; matching n/nInput aliases; string scientific notation rejected. JSON numeric finite rounding is permitted; raw nonzero underflow rejected.
• Scientific display uses the first12 digits without rounding; exact contains every digit.
• Unknown fields → UNKNOWN_INPUT; aliases disagree → INPUT_ALIAS_CONFLICT; excessive text → INPUT_TOO_LARGE