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Public evidence

math.square_root

Machine-checked verification for calculation version 1.0.4 · tier engine_tested

CVP status

CVP VERIFIED · CVP protocol 1.0.0-proposed · Core assurance

Declared partitions are positive-real, zero, negative-imaginary, tiny-subnormal, large-finite, invalid-domain — not a whole-domain claim. x < 0 is the published principal imaginary √|x| i, not invalid-domain. Complete-result comparison includes both branches, min-subnormal and max-finite; strict decimal parsing and raw underflow rejection.

Declared partition coverage
PASS · 6/6 declared partitions (positive-real, zero, negative-imaginary, tiny-subnormal, large-finite, invalid-domain)
Versions
Calculation 1.0.4 · CVP protocol 1.0.0-proposed · Evidence 2026-10-26.square-root-complete-contract-v1
Verification revision
2026-10-26.square-root-complete-contract-v1 · 4/4 property · digest 767ce88755a9

Verification

Legacy regression suite: 18/18 calculation tests · Production surface contract 6/6

Three distinct suites: educational examples on the calculator page, this legacy regression count (18/18 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 2026-10-26.square-root-complete-contract-v1. Calculation version 1.0.4. CVP 1.0.0-proposed. 80/80 golden · 7/7 CVP boundary · 11/11 invalid · 4/4 property · 2/2 metamorphic · 3/3 round-trip · 7/7 cross-interface · 5/5 URL→result→graph · 6/6 CVP contract. digest 767ce88755a9. 80 fixed and seeded complete results including both signs, zero, subnormal, max finite and rounding neighbors; not exhaustive

  • Golden (oracle-backed) 80 / 80
  • CVP boundary 7 / 7
  • Invalid input 11 / 11
  • Property 4 / 4
  • Metamorphic 2 / 2
  • Round-trip 3 / 3
  • Cross-interface 7 / 7
  • URL → result → graph 5 / 5
  • CVP contract 6 / 6
  • Interfaces PASS · UI (SSR) / REST / MCP / URL→result→graph
  • Interface claim Success 4/4. Error-path engine·REST·MCP 3/3 (status, code, calculation_version). SSR compared on URL-canonical requested calculations; empty query is idle (not an error) and JSON-typed object/array inputs are REST/MCP-only. Integration: URL → SSR result → Live graph current point (5/5). Hydration/slider/history are URL-canonical contracts, not a live browser session. Live-browser hydration, slider, Copy JSON, and Overview/Focus are covered in the current full review; Core ui-ssr is not a 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:c5f09468ffa8ad03d95114a4a2621da17c7336834988fca78c1bfad2f9f3b341

Input schema sha256:69b9b78cd467274524000030ed067a5c87391b85c6af4b7d168f00914a774f79 · Output schema sha256:dfb5553c678fd2ff8916c23d13c5350a0fde5ceadb85438461be5492923fc37f · 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
square-root
Engine
square-root
Engine build
2026-10-26
Evidence core
2026-10-26T05:34:16.140Z
Rendered
2026-10-28T03:01:57.873Z
Last reviewed
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Assumptions

  • Principal branch: nonnegative real root when x ≥ 0.
  • Unlike Log / Ln, this engine does not reject x < 0. It returns the principal imaginary √|x| i, not a real error.
  • The other real root for x > 0 is −√x; the other imaginary root for x < 0 is −√|x| i. The published value is the principal one.

Limitations

  • Principal branch on finite real radicands: x≥0 gives real=principal=√x,imag=0; x<0 gives real=0,imag=√|x|,principal=null. Both real/imag/principal are always present.
  • Numbers or strict decimal/scientific strings of at most512 characters; x and xInput must agree. Unknown keys, nonfinite values, null, booleans, hex, commas and nonzero-to-zero underflow reject.
  • Binary64 input rounding and Math.sqrt output rounding are distinct; at most2 ULP on declared independent Decimal2000 reference vectors, not an exhaustive or exact-decimal guarantee. Relative condition number1/2 away from zero; derivative unbounded at zero.
  • 12 significant digit display. Perfect-square claims require safe-integer radicands and roots. Scaled Babylonian working is an illustration, not the engine algorithm.
  • Live graph shows the real branch in a bounded window; negative radicands have no real point. Typing computes locally; shared URLs and REST/MCP send inputs and may enter logs.

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.