[Crm-sig] Preferred Identifier vs Appellation vs Image

Vladimir Alexiev vladimir.alexiev at ontotext.com
Tue Nov 20 12:57:45 EET 2012

CRM has one notion of preferredness:
0. crm:P48_has_preferred_identifier.

However, in any system that displays search results, it's important to know two other preferred attributes of an object:
1. Preferred image: to be shown as thumbnail in a result list or lightbox
2. Preferred label (name/title/appellation): to be shown as short textual representation of the object

In ResearchSpace we've tackled this in some way, even though imperfect:
1. For BM data: subproperty bmo:PX_has_main_represesentation of crm:P138i_ has_representation
   For RKD data: subclass rso:E38_Main_Image of crm:E38_Image
2. Following LOD best practice, we try to make rdfs:label for every object.
   This is rife with its own problems, e.g. because thesaurus terms have a different one (skos:prefLabel).

I wonder why CRM standardizes 0 but not 1 & 2. It seems to me the notion of preferred identifier is least useful of the three because:
- when you integrate data from various systems (CRM's forte), each will come with it's own notion of primary key, so there won't be agreement on "preferred identifier".
  In contrast, there may well be agreement on preferred image (e.g. full frontal) and appellation (e.g. official title)
- users do not (or should not) care about identifiers


Let's say we have these attributes and want to add that they are preferred:
 <obj> P1_is_identified_by <obj/id/1>; 
   P102_has_title <obj/title/1>; 
   P138i_has_representation <obj/image/1.jpg>

There are various ways:

A. With a subclass (like rso:E38_Main_Image above)
B. With a subproperty (like crm:P48_has_preferred_identifier or bmo:PX_has_main_represesentation above)
C. With a property-property: P102.1 has type, P138.1 mode of representation (curiously, there's no P1.1)
D. With a type in the attribute. E.g.:
  <obj/id/1> P2_has_type <id/preferred>; P3_has_note "2926".
  <obj/title/1> P2_has_type <title/preferred>; P3_has_note "De badende Suzanna".
  <obj/image/1.jpg> P2_has_type <image/preferred>; P2_has_type <format/jpeg>.
E. With a type in the Attribute Assignment, as per P48's scope note: 
  "The fact that an identifier is a preferred one for an organisation
   can be better expressed in a context independent form by assigning a suitable E55 Type
   to the respective instance of E15 Identifier Assignment"

I tend towards D, with a property such as "P200 is preferred" on E1

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