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This type provides information on an existing entity with changed label data.

Discussion:

May include additional change types beyond LABEL_CHANGE.  Would it make more sense to have a DELETE_LABEL + ADD_LABEL for changing label?

If DELETE_LABEL is supported, is there a concept of minimally viable data required for a valid entity and would this include a primary label?  Thus, when the primary label is removed, does it require a replacement label?  What happens for primary label if there is a delete but no add?  Probably not a problem because primary label is likely to be minimal required data for a valid record.

If DELETE_LABEL is supported, is it ok for a variant label to be deleted and not have a corresponding add?  This seems ok. 
This specifically meets the need of applications that cache labels.  Question whether there should be caching of labels in downstream consumers?  Several indicate that this is common practice.  For example, Sinopia caches labels to avoid having to dereference URIs when viewing the data.  Others cache labels when creating indices for searching.

Discussion on Primary Label:

• Primary label may not be a human understandable label.  For example, ISNI number is primary label in the ISNI authority.
• Although it is common for primary label to be a single value, some authorities may allow multiple values for the primary label.  For example, Wikidata has multiple primary labels for different languages and some may be missing for

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• some

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• languages.

• In some authorities, the primary label is critical and in others it may be optional or used for convenience.

• The predicate used to identify primary and variant labels can, and commonly do, differ between authorities.

• If DELETE_LABEL is supported, is there a concept of minimally viable data required for a valid entity and would this include a primary label?  Thus, when the primary label is removed, does it require a replacement label?  What happens for primary label if there is a delete but no add?  Probably not a problem because primary label is likely to be minimal required data for a valid record.

Discussion on Variant Labels:

• It is common for there to be multiple variant labels.  In some cases, variants may represent different languages.

• If DELETE_LABEL is supported, is it ok for a variant label to be deleted and not have a corresponding add?  This seems ok. 

Examples:

• LOC is looking at using a feed that provides information on authoritative labels.  This is mostly used for name changes (e.g. person died and the death date is added to the label).

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To be able to replace a label, also need:

• REPLACESOLD_LABEL - the value of the literal that is being replaced

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{ 
  "type": "LABEL_CHANGE",
  "URI": "https://uri.of.changing.entity",
  "PREDICATE": "skos:prefLabel",
  "NEW_LABEL": "new value"@en,
  "OLD_LABEL": "old value"@en 
}

{ 
  "type": "LABEL_CHANGE",
  "ADD": "https://uri.of.changing.entity",
  "PREDICATE": "skos:prefLabel",
  "NEW_LABEL": "new value"@en,
  "OLD_LABEL": "old value"@en 
}

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