Provenance Gap Year Span Calculator
Union overlapping documented ownership intervals and retain all gaps inside caller half-open review years; unlike event-date spacing, overlapping documentation is not double-counted and gaps are not proof of unlawful ownership.
Description
Provenance documentation can overlap and leave gaps.
Provenance documentation can overlap and leave gaps. Unioning intervals measures coverage without counting the same year twice.
Union overlapping documented ownership intervals and retain all gaps inside caller half-open review years; unlike event-date spacing, overlapping documentation is not double-counted and gaps are not proof of unlawful ownership.
When to use Provenance Gap Year Span Calculator
Use this tool to union overlapping documented ownership intervals and retain all gaps inside caller half-open review years; unlike event-date spacing, overlapping documentation is not double-counted and gaps are not proof of unlawful ownership.
Prepare the collection, exposure, scheduling or financial records required for this calculation. Keep row order and the declared units consistent.
How to use Provenance Gap Year Span Calculator and understand its results
- Prepare the collection, exposure, scheduling or financial records required for this calculation. Keep row order and the declared units consistent.
- Enter documentedOwnershipYearIntervals, reviewYearBounds using the field table and calculation rules, then run the tool.
- Read undocumentedYearIntervals, totalUndocumentedYears, documentedUnionYears. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| documentedOwnershipYearIntervals | Documented ownership year intervals | list of list of number | Required |
| reviewYearBounds | Review year bounds | list of number | Required |
Supply a positive-duration half-open review window and nonempty ordered ownership pairs. Sort and merge touching or overlapping intervals, clip them, and return every gap plus documented and undocumented totals.1
undocumented years = review span − documented union clipped to review Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| undocumentedYearIntervals | Undocumented year intervals | list of list of number |
| totalUndocumentedYears | Total undocumented years | number |
| documentedUnionYears | Documented union years | number |
{
"input": {
"documentedOwnershipYearIntervals": [
[
1900,
1920
],
[
1910,
1930
],
[
1940,
1950
]
],
"reviewYearBounds": [
1900,
1950
]
},
"output": {
"undocumentedYearIntervals": [
[
1930,
1940
]
],
"totalUndocumentedYears": 10,
"documentedUnionYears": 40
}
}Limitations and assumptions
A documentation gap is not proof of unlawful ownership.
Numbers and computed results must be finite; overflow produces an error. Matrices are limited to 128 rows and 128 entries per row; other numeric lists are limited to 100,000 entries. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.
Alternative or Complementary methods
Use Nazi-Era Red Flag Date Range Overlap Checker: Flag documentary intervals overlapping caller declared historical review window using half-open years and union exposure; named Nazi-era review does not itself establish theft, restitution eligibility or clear provenance. For a complementary task, use Deaccession Justification Criteria Checklist Completeness Checker: Audit deaccession documentation against caller required/blocking criteria while retaining missing evidence; completeness is not ethical/legal authorization to dispose of collection objects.
References
-
Provenance Gap Year Span Calculator — tool.io
Similar or alternative tools
- Nazi-Era Red Flag Date Range Overlap Checker
Flag documentary intervals overlapping caller declared historical review window using half-open years and union exposure; named Nazi-era review does not itself establish theft, restitution eligibility or clear provenance.
- Deaccession Justification Criteria Checklist Completeness Checker
Audit deaccession documentation against caller required/blocking criteria while retaining missing evidence; completeness is not ethical/legal authorization to dispose of collection objects.