[Crm-sig] New Issue: Common Policy / Method for Implementing the .1 Properties of Base and Extensions in RDF

Philippe Michon illipmich at gmail.com
Tue Apr 5 21:52:33 EEST 2022

Dear all,

I strongly second this proposal. In my opinion, there is a serious lack of
guidance as to how we are supposed to use .1 properties. In my opinion, the
management of PCs should not only be considered in order to overcome a
technological limit. I believe there is some interesting semantics within
PCs that would be worth describing more formally.

If I'm not mistaken, .1s are only very briefly described in the CRMbase
specification. I quickly found only five snippets (I didn't include the new
proposals about .1 properties in 7.2.1):


   In the "Terminology" section under "property": " Properties may
   themselves have properties that relate to other classes (This feature is
   used in this model only in order to describe dynamic subtyping of

   in the "About the logical expressions used in the CIDOC CRM":
   "properties of properties, “ .1 properties” are named by ternary predicate
   symbols; conventionally, we use P14.1 as the ternary predicate symbol
   corresponding to property P14.1 in the role of. "

   in the "Extensions of CIDOC CRM": "Existing properties can be extended,
   either structurally as subproperties, or in some cases, dynamically, using
   properties of properties which allow subtyping (see section About Types

   in "Specific Modelling Constructs" under "About Types": "Analogous to
   the function of the P2 has type (is type of) property, some properties in
   the CIDOC CRM are associated with an additional property. These are
   numbered in the CIDOC CRM documentation with a ‘.1’ extension. The range of
   these properties of properties always falls under E55 Type. The purpose of
   a property of a property is to provide an alternative mechanism to
   specialize its domain property through the use of property subtypes
   declared as instances of E55 Type. They do not appear in the property
   hierarchy list but are included as part of the property declarations and
   referred to in the class declarations. For example, P62.1 mode of
   depiction: E55 Type is associated with E24 Physical Man-made Thing. P62
   depicts (is depicted by): E1 CRM Entity"

   and in "CIDOC CRM Class Declarations": "Properties of properties are
   provided indented and in parentheses beneath their respective domain

My questions and comments:


   I believe it would be particularly important to clarify if it is
   possible to use the .1 property of a superproperty with one of its
   subproperties. For example, is it allowed to use P3.1_has_note with
   P190_has_symbolic_content? According to my understanding this is not
   possible, but I do not believe it is explained anywhere. And if it is
   indeed possible, the PC extension does not allow this semantics.

   Another issue is the fact that "PC0_Typed_CRM_Property" is not part of
   the CRMbase class hierarchy. I can understand the reasons behind this
   choice, but again these would need to be defined. In the context of our
   work at CHIN, we would sometimes have appreciated using a "P2_has_type" on
   a PC class in order to type it more formally. Is this something the SIG
   would encourage?

   There is also an issue with P67_refers_to and P138_represents. The last
   is a subproperty of the first and both have a .1 property. In the PC
   extension, this hierarchy is completely lost, which limits the
   possibilities of inference. I don't know how to manage this according to
   CRMpc, but this problem should at least be documented if there is no
   concrete solution. I don't believe identifying PC138_represents as a
   subclass of PC67_refers_to would completely resolve this issue. Moreover,
   this representation would again raise the question concerning the
   inheritance of .1 properties by subproperties.

   In the same vein, the question of the relationship that exists between
   the structure of PCs and their corresponding CRMbase properties is not
   explicit. If a user wants to implement P67_refers_to and PC67_refers_to in
   their knowledge graph, how should they implement the whole thing? Should
   the ontology support this kind of inference (in the RDF), or should it be
   handled at the query level?

   I also believe that it would be important to standardize the names of
   the PC entities. For example, why are the first letters of
   "PC0_Typed_CRM_Property" capitalized while other classes are not (eg.

   Now that we formalize the .1 properties, I think it would be more than
   necessary to have an official scope note for each of them. The vast
   majority are only very poorly documented in the scope note of their
   respective property. It is also important to mention that
   "PC0_Typed_CRM_Property", "P01_has_domain", and "P02_has_range" don't have
   a scope note at all.

   It is also difficult to easily find all the information about .1
   properties. Would it be useful to have a dedicated section for them in the



Le jeu. 24 mars 2022 à 08:51, Martin Doerr via Crm-sig <crm-sig at ics.forth.gr>
a écrit :

> I think this is a good idea!
> Martin
> On 3/24/2022 1:23 PM, Pavlos Fafalios via Crm-sig wrote:
> Dear George, all,
> The new version of PC classes file (for CRMbase version 7.1.1) has been
> already produced (as discussed in the last meeting) and will be soon
> available through the crm website (see issue 567
> <https://cidoc-crm.org/Issue/ID-567-module-for-pc-properties>).
> Thinking of it again:
> Since the namespace for the PC classes is the same with that of the base
> classes/properties, why not including them directly within the base RDFS?
> (i.e. providing at the end a single rdfs file that also includes the PCs).
> Properties of properties are part of the official documentation (of the
> base model, or of an extension), so why not including the corresponding PC
> classes in the same RDFS file instead of providing and maintaining a second
> file? (this applies for both the base model and the extensions)
> This is just a suggestion without knowing any discussions, or decisions
> made, when implementing the PC classes for the first time several years ago
> (there might be a good reason for having a second file...).
> Best regards,
> Pavlos
> On Thu, Mar 24, 2022 at 11:41 AM George Bruseker via Crm-sig <
> crm-sig at ics.forth.gr> wrote:
>> Dear all,
>> Subsequent to another thread I started here I am proposing that there be
>> a conversation about having a standard policy and method for creating,
>> documenting and making available the .1 properties for base and its
>> extensions in the RDF serialization. At present to my knowledge the PC
>> classes are only available for CRMBase and relative to version 6.2.1. Other
>> extensions however also use .1 constructions and, moreover, CRMbase moves
>> forward and its PC classes should hypothetically move with it. Therefore, I
>> propose we discuss, create and implement a common policy for creating this
>> rdf derivative to support rdf implementations that adopt the .1
>> constructions.
>> Best,
>> George
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> --
> Pavlos Fafalios
> Postdoctoral researcher (Marie Curie IF - Project ReKnow
> <https://reknow.ics.forth.gr/>)
> Centre for Cultural Informatics & Information Systems Laboratory
> Institute of Computer Science - FORTH
> and
> Visiting Lecturer
> Department of Management Science & Technology
> Hellenic Mediterranean University
> Address: N. Plastira 100, Vassilika Vouton, 70013 Heraklion, Greece
> Email: fafalios at ics.forth.gr
> Tel: +30-2810-391619
> Web: http://users.ics.forth.gr/~fafalios/
> _______________________________________________
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> --
> ------------------------------------
>  Dr. Martin Doerr
>  Honorary Head of the
>  Center for Cultural Informatics
>  Information Systems Laboratory
>  Institute of Computer Science
>  Foundation for Research and Technology - Hellas (FORTH)
>  N.Plastira 100, Vassilika Vouton,
>  GR70013 Heraklion,Crete,Greece
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*Philippe Michon*

(he/il – https://name.pn/philippe-michon)

Semantic Web Analyst
Canadian Heritage Information Network (CHIN)
Department of Canadian Heritage, Government of Canada
1030 Innes Road, Ottawa (Ontario) K1B 4S7
Philippe.Michon at canada.ca

illipmich at gmail.com
Tel: 613-998-3721 ext. 225 or 1-800-520-2446

Analyste en web sémantique
Réseau canadien d'information sur le patrimoine (RCIP)
Ministère du Patrimoine canadien, Gouvernement du Canada
1030 chemin Innes, Ottawa (Ontario), K1B 4S7
Philippe.Michon at canada.ca

illipmich at gmail.com
Tél. : 613-998-3721 poste 225 ou 1-800-520-2446
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