Source: https://guthlabs.ai/docs/instruments/parallel-axis-theorem-calculator/implementation/

instrument implementation / implementation-contract

# Parallel Axis Theorem Calculator implementation

A source-bound implementation contract for Parallel Axis Theorem 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**: t4-010

**Effect**: Computation or source lookup only

## Input and validation requirements

An extreme but representable-looking input causes the plain JavaScript arithmetic to overflow A d² to Infinity. The calculator should reject or flag non-finite inputs and outputs. The specification has no denominator trap and no genuine formula regime switch.

## 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": {
    "I_c": 200000,
    "A": 6000,
    "d": 50,
    "units": "mm⁴, mm², mm"
  },
  "expected_outputs": {
    "I": 15200000,
    "units": "mm⁴"
  },
  "working": "d² = 50² = 2,500 mm². Ad² = 6,000 × 2,500 = 15,000,000 mm⁴. I = I_c + Ad² = 200,000 + 15,000,000 = 15,200,000 mm⁴."
}
````

## Other records

[01**Overview**](<https://guthlabs.ai/docs/instruments/parallel-axis-theorem-calculator/>)[02**Mechanism**](<https://guthlabs.ai/docs/instruments/parallel-axis-theorem-calculator/mechanism/>)[04**Qualification**](<https://guthlabs.ai/docs/instruments/parallel-axis-theorem-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-tranche4/tranche4-results.json`