Source: https://guthlabs.ai/docs/instruments/big-number-arbitrary-precision-calculator/implementation/

instrument implementation / implementation-contract

# Big Number / Arbitrary Precision Calculator implementation

A source-bound implementation contract for Big Number / Arbitrary Precision Calculator; deployment and executable qualification remain separate.

Status: **VERIFIED_CLEAN**Lifecycle: **implementation-contract**

## Binding contract

This record describes what an executable surface must bind and validate. It does not claim that a public calculator, package, or production route is deployed.

**Record owner**: Guth Instruments

**Lifecycle**: verified-clean

**Evidence ID**: t8-039

**Effect**: Computation or source lookup only

## Input and validation requirements

The specification does not define division-by-zero behavior or unary-minus versus exponentiation precedence. An implementation can therefore produce an invalid non-error result for 1 / 0 or disagree on the value of -3^2, despite supporting arbitrary precision.

## Required corrections

No binding erratum is attached to this unique-name record. Implementers must still preserve the declared units, domain, and failure behavior.

## Inspectable interface fixture

The sample below is evidence for interface and validation tests, not a production implementation.

````
{
  "inputs": {
    "expression": "0!",
    "domain": "factorial"
  },
  "expected_outputs": {
    "result": "1",
    "type": "exact_integer"
  },
  "reference_data": {
    "identity": "0!=1",
    "algorithm": "factorial(n)=1*2*...*n with the empty product defined as 1"
  },
  "working": "0! is the empty product. By definition, 0!=1."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/big-number-arbitrary-precision-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/big-number-arbitrary-precision-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/big-number-arbitrary-precision-calculator/qualification/>)

## Sources and evidence

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

- `VERIFIED_LEDGER.json`

- `evidence-tranche8/tranche8-results.json`