Bounded answer
Preserve IANA zone identifier, tzdb version, resolved offset, fold or gap state, and conversion receipt. Bind those fields to one canonical input manifest and receipt before interpreting or sharing an output.
Input contract
What must be fixed first
Canonical input manifest
Named algorithm and dependency versions
Declared units and conventions
Retention and redaction policy
Procedure
Work the decision in order
- 1
Normalize the input without dropping uncertainty.
- 2
Record IANA zone identifier, tzdb version, resolved offset, fold or gap state, and conversion receipt.
- 3
Run the named deterministic operation.
- 4
Bind inputs and outputs into a receipt.
- 5
Verify the receipt independently before interpretation.
Expected outputs
- Canonical manifest
- Calculation or transformation receipt
- Reproducibility and redaction statement
Refuse when
- Historical UTC conversion can change when time-zone rules or the selected occurrence of an ambiguous time differ.
- Required input, unit, convention, or dependency version is absent.
- An interpretive preference selects the computational convention after outputs are seen.
Questions this guide answers
What must a machine preserve for time-zone database version?
Preserve IANA zone identifier, tzdb version, resolved offset, fold or gap state, and conversion receipt.
Which information must be versioned?
At minimum, preserve IANA zone identifier, tzdb version, resolved offset, fold or gap state, and conversion receipt, together with the canonical input and output digests.
When should an output be withheld?
Withhold it when historical UTC conversion can change when time-zone rules or the selected occurrence of an ambiguous time differ. or when a required dependency cannot be identified.
Does determinism validate the interpretation?
No. Determinism makes the computation reproducible; interpretive or predictive validity requires a separate prospective evaluation.
What belongs in the receipt?
The operation, canonical inputs, units, assumptions, dependency versions, outputs, uncertainty treatment, and package digest.
Limits
- Historical UTC conversion can change when time-zone rules or the selected occurrence of an ambiguous time differ.
- Reproducible astronomical arithmetic does not validate an astrological interpretation or prediction.
- No missing number, uncertainty interval, or calculation receipt is invented.