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Public evidence

math.exponential_growth

Machine-checked verification for calculation version 1.0.10 · tier engine_tested

CVP status

CVP VERIFIED · production STALE · CVP protocol 1.0.0-proposed · Engineering assurance

periodic r > −100%; continuous uses k=ratePct; inverse solves any missing field among x₀, r, t given x(t)

Declared partition coverage
PASS · 7/7 declared partitions (forward-periodic, forward-continuous, inverse-time, inverse-x0, inverse-rate, verify, invalid-domain)
Versions
Calculation 1.0.10 · CVP protocol 1.0.0-proposed · Evidence 2026-10-28.meta-metrics-v2
Verification revision
2026-10-28.meta-metrics-v2 · 3/3 property · digest 3c510e301f33

Verification

Legacy regression suite: 20/20 calculation tests · Production surface contract 29/29

Three distinct suites: educational examples on the calculator page, this legacy regression count (20/20 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.

    STALE · Build schema 1.0.10 matches page · production binding STALE · Semantic contract ✓ · Last attestation PASS · current evidence changed · re-attestation required · CVP STALE · attestation STALE — Production CURRENT withheld · Public/cache ✓ · Origin ✓

CVP verification suite

Protocol checks from the Evidence Manifest. Distinct from the legacy regression suite above. Verification revision 2026-10-28.meta-metrics-v2. Calculation version 1.0.10. CVP 1.0.0-proposed. 69/69 golden · 6/6 CVP boundary · 10/10 invalid · 3/3 property · 1/1 metamorphic · 3/3 round-trip · 13/13 O3 · 65/65 cross-interface · 4/4 URL→result→graph · 29/29 CVP contract. digest 3c510e301f33. Listed independent reference vectors only; no whole-domain/runtime guarantee.

  • Golden (oracle-backed) 69 / 69
  • CVP boundary 6 / 6
  • Invalid input 10 / 10
  • Property 3 / 3
  • Metamorphic 1 / 1
  • Round-trip 3 / 3
  • O3 high-precision 13 / 13
  • Cross-interface 65 / 65
  • URL → result → graph 4 / 4
  • CVP contract 29 / 29
  • Interfaces PASS · UI (SSR) / REST / MCP / URL→result→graph
  • Interface claim Success 65/65. Integration: URL → SSR result → Live graph current point (4/4). Hydration/slider/history are URL-canonical contracts, not a live browser session.
  • Assurance Engineering
  • 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
  • input schema declares xt PASS
  • input schema accepts inverse time PASS
  • input schema accepts verify PASS
  • input schema rejects two fields PASS
  • output schema defines consistency PASS
  • input schema forward PASS
  • rest forward output schema PASS
  • rest forward consistency PASS
  • input schema forward continuous PASS
  • rest forward continuous output schema PASS
  • rest forward continuous consistency PASS
  • input schema inverse time PASS
  • rest inverse time output schema PASS
  • rest inverse time consistency PASS
  • input schema inverse x0 PASS
  • rest inverse x0 output schema PASS
  • rest inverse x0 consistency PASS
  • input schema inverse rate PASS
  • rest inverse rate output schema PASS
  • rest inverse rate consistency PASS
  • input schema verify PASS
  • rest verify output schema PASS
  • rest verify consistency PASS
  • rest success payload validates schema PASS

Fingerprint sha256:68947c81a7e1e01ead66fea13c45ac50d22f17a830a8bb2bc160e954bffeb57d

Input schema sha256:13a1effa428dd818fc8ef364cfff535cb4df0c12eb408082956e6754db077e94 · Output schema sha256:385313ac973965b21ef22040ca11ef747adfce7b6f7f5fce800529c78abfd27e · 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.

Build & scope

Engine identity and declared limitations.

Tool
exponential-growth
Engine
exponential-growth
Engine build
2026-10-27
Evidence core
2026-10-27T05:26:03.915Z
Rendered
2026-10-28T03:01:57.886Z
Last reviewed
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Assumptions

  • Constant rate over the interval (real populations often need logistic models long-term).
  • CalculatorX defines the periodic model domain as r > −100% so the growth factor stays positive and inverse/logarithmic solving remains well-defined.

Limitations

  • Periodic x(t)=x0(1+r/100)^t requires r>-100%; continuous x(t)=x0 exp(k t) uses ratePct=k per time unit, not percent. Signed amplitudes allowed; inverse time/rate require matching nonzero signs.
  • Provide any three fields or four to compare calculated xt using display quantization. Zero rate/time can make inverses undefined or nonunique. Blank/null fields are missing.
  • Strict decimal/scientific text up to512 characters; nonzero input rounding tozero rejects NUMERIC_UNDERFLOW. Conflicting aliases/unknown fields/models reject. Output is finite unrounded binary64; overflow/underflow reject.
  • Independent Decimal1200/1600 fixed vectors use predeclared4e-12 relative budget plus2 subnormal quanta, strictzero/sign/type. Legacy O3 remains separately tested32ULP. No whole-domain or cross-runtime guarantee; inverse conditioning degrades at zero rate/time and amplitude ratios near1.
  • Typing local; shared URLs, REST and MCP transmit inputs and may enter logs. Native exports retain scalar and provided raw inputs.

Sources

Standards and references supporting this tool specification. Methods are listed separately — they are algorithms, not bibliographic sources.

Verification disclosure

Aggregate outcomes, scope and artifact commitments are public. Complete test inputs, expected values, execution records and oracle infrastructure are retained privately. This summary does not independently reproduce the full verification run.