[Crm-sig] Scope note for E55 Type

Christian-Emil Ore c.e.s.ore at edd.uio.no
Sun Oct 19 22:41:59 EEST 2008


Dear all,
In the SIG meeting at CIDOC 2008 in Athens I was asked to write a draft 
for a new scope note for E55 Type and adjust the paragraphs about types 
in the introduction. Yuo will find my suggestion for the scope note 
below. I postpone the intro part until a decision in taken on the scope 
note.

The scope note is based on the original and on Guenther's suggestion 
from May. The intention has been to make the scope not more explicit on 
E55 Type's function as an interface to external classification systems 
and to avoid the use of the term 'meta class'. In my opinion a type in 
the CRM is a term, concept or predicate. It is not equal to the set 
denoted by this term. Martin pointed out in an email that there is very 
little difference between the interpretation of a CRM class and this 
interpretation of a type, eg 'information carrier' (CRM class) and 
'wineclass' type.

I agree that any CRM class (as a concept) and and instance of E55 have 
the same extensional intentional set/term duality. A difference is that 
we do not have any mechanisms inside CRM (if we do not follow the 
suggestion from Vladimir Ivanov) to speak about a CRM class as a whole 
as we can with respect to an instance of E55. So even though 'wineglass' 
  seen from a bird's view of the model is the same beast as 'information 
carrier' (hypothetical sets of something), there is a difference in the 
model qua a formal system.

Regards,
CHristian-Emil






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NEW TEXT E55 Scope Note
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E55
Type

Subclass of:    E28 Conceptual Object
Superclass of:  E56 Language
                 E57 Material
                 E58 Measurement Unit

Scope note:

The class E55 Type comprises concepts (universals) and hence provides an 
interface to domain specific concepts external to the CRM.  In this 
fashion, a connection between the CRM and a particular (external) domain 
concept as a subclass of E55 Type can be established.

This hierarchical relation allows for additional refinement through 
sub-typing of the classes (of the CRM) which represent important 
typological distinctions but where the given user group does not 
consider it necessary to give a further analysis of the classes by 
extending the CRM with new sub classes. The interpretation of these 
sub-types is based on the agreement of the specific groups.

A type, that is, an instance of E55 Type can be interpreted in several 
ways. It can be seen as a term in a thesaurus or as predicate with a 
free variable in a logical system. The instances of  the CRM classes 
having a given type (e.g. through  P2 has type) at a given point in time 
form a set or a class. However, this class or set is not identical to 
the type.

E55 Type reflects the characteristic use of terms like "Object Type", 
"Category", "Classification" etc in museum documentation. Such fields 
are used for terms that declare that the object belongs to a particular 
category or class of items.  It has however nothing to do with the term 
`type' in Natural History (cf. E83 Type Creation) which is a E24 
Physical Man-Made Thing (eg an dried insect on a needle) . But E55 Type 
includes the notion of a `taxon' which are concepts.

Ideally, (external) subclasses of the class E55 Type should be organised 
into thesauri, with scope notes, illustrations, etc. to clarify their 
meaning.  In general, it is expected that different domains and cultural 
groups will develop different thesauri in parallel.  Consistent 
reasoning on the expansion of subterms used in a thesaurus is possible 
insofar as it conforms to both the classes and the hierarchies of the 
CRM.  E56 Language, E57 Material and E58 Measurement Unit have been 
defined explicitly as elements of the E55 Type hierarchy because they 
are used categorically in the CRM without reference to instances of 
them, i.e. the CRM does not foresee the description of instances of 
instances of them, e.g., the property instance `P45 consists of : gold' 
does not refer to a particular instance of gold.


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