Issue 288: Issue about P82 and P81 usage
Posted by Jean-Baptiste Pressac on 18/06/2015
I am an computer-scientist working with two researchers on a prosopographic database of people who contributed to literature in Breton, a Celtic language of Bretagne (France) and I am interested to use the CIDOC-CRM (in particular FRBRoo) to share our data in RDF format.
The database stores informations like the dates of birth, death, participation to groups of all kinds, studies... Informations where fuzzy times are legion. I read the PDF document How to implement CRM Time in RDF (response to issue 164) but I need to clarify the use of P81a, P81b, P82a and P82b.
I understood that any "date" is considered as a duration in the CRM. Even a birth occurring on 25Th of July 1815 should be considered as an event occurring between for instance 25-7-1815 at 0:00 and 25-7-1815 at 24:59. But in that case, what could be the values of P81a, P81b, P82a and P82b ? If we don't take the hours and minutes into account, should we consider the following: P82a = P81a = P81b = P82b = 25-7-1815 ? Or should we consider that we only know P82a and P82b (and don't know anything about a narrower duration, thus P81) and could only declare the following:
P82a = P82b = 25-7-1815
P82a = 25-7-1815 at 0:00
P82b = 25-7-1815 at 23:59
If I take the example of the event (p.5 of the Definition of the CIDOC Conceptual Reference Model) "my birth day celebration 28-6-1995 (E7)" and guess that you invited your friends at 17:00 and the last one left your house around 23:00, should we say that the minimum known temporal extent is between 28-6-1995 17:00 and 28-6-1995 22:45 and the maximum know temporal extent is between 28-6-1995 17:00 and 28-6-1995 23:15, thus:
P82a = P81a = 28-6-1995 17:00
P81b = 28-6-1995 22:45 (23:00 arbitrarily subtracted with 15 minutes)
P82b = 28-6-1995 23:15 (23:00 arbitrarily added with 15 minutes)
Another example: An author is know to have been elected to a club during February and March 1754 and to have left the club in 1761. Should we declare a E85 Joining with a E52 Time Span characterized by:
P82a = 01-02-1754
P82b = 31-12-1754
And a E86 Leaving with a E52 Time Span characterized by:
P82a = 01-01-1761
P82b = 31-12-1761
Last example: If we are talking about a war which started between February and March 1756 and finished in 1773, should we declare an E7 Activity with a E52 Time Span characterized by:
P82a = 01-02-1756
P81a = 31-04-1756
P81b = 31-12-1773
P82b = 31-12-1773
Posted by Jean-Baptiste Pressac on 15/09/2015
Some months after my issue about P82 and P81 usage I still don't figure out how to solve my problem. Do you have any clue to help me ?
In 34th meeting, it is decided that if two inner bounds are not known, we give the outer bounds. It is decided a good practice guide to be written by MD and CEO. MD will write about negative inner bounds.
Heraklion, October 2015
posted by Christian Emil on 6/12/2016
The issue was raised back in June 2015 and has hardly any relevance for the project anymore.
Jean-Baptiste Pressac, who wrote the email, refer to a document called " How to implement CRM Time in RDF", a post to the crm-sig-list by Vladimir A. I have not found another document about this.
They are in the rdf-definition of CRM defined as pairwise sub properties of P81, and P82 respectively. I cannot find them in the text definition of CRM.
Slide 12 in the attached pdf from 2013 illustrates the definition of the 4 properties. The slide also illustrates that P81a is not a sub property of P81. When the a time primitive is interpreted as an interval in a linear time line the P81a points to the start point of this (open) interval. If P81a is a sub property of P81 then an instance of P81a is also an instance of P81 and there may be a second instance of P81a defining the start point of the first which may give a recursion we may not want.
The primitive time relations between E2 temporal entities should also be taken into consideration:
A E2 temporal entity has one and only one E52 Time-Span. An instance of E52 Time-Span has one and only one E61 Time Primitive connected via E81 Ongoing throughout and E82 occurs within respectively. Thus indirectly every instance of E2 Temporal Entity has one and only one instance of E61 Time Primitive via P2 ○ P81 and correspondingly one and one E61 Time Primitive via P2 ○ P82.
If two instances of E2 temporal enitiy are related via an instance of Pxx, then there should be some relation between their corresponding pairs of E61 Time Primitive such that the PXX are "implemented" by the relations between the (pairs of) E61 Time Primitive.
Next: If P81 and P82 are seen as approximations to the "real" temporal extent, then the cardinality of the two should be weakened to many to many, necessary (1,n:0,n).
The P81a, P81b, P82a, P82b are not a part of CRM and but may be parts of an implementation of E61 as intervals on a linear timeline.
An implementation of E61 Time Primitive should include relationships which make the implementation consistent with the relationships between the instances of E2 Temporal Entities.
The cardinality of P81 and P82 should be weakened to many to many, necessary (1,n:0,n).
P81 ongoing throughout
Domain: E52 Time-Span
Range: E61 Time Primitive
Quantification:many to one, necessary (1,1:0,n)
Scope note:This property describes the minimum period of time covered by an E52 Time-Span.
Since Time-Spans may not have precisely known temporal extents, the CRM supports statements about the minimum and maximum temporal extents of Time-Spans. This property allows a Time-Span’s minimum temporal extent (i.e. its inner boundary) to be assigned an E61 Time Primitive value. Time Primitives are treated by the CRM as application or system specific date intervals, and are not further analysed.
In the 37th joined meeting of the CIDOC CRM SIG and ISO/TC46/SC4/WG9 and the 30th FRBR - CIDOC CRM Harmonization meeting, the crm-sig discussed the proposal of Christian - Emil and decided that this issue cannot be solved without addressing the overall issues discussed in issue 309. To contribute to / consider within that overall discussion it should be decided how time primitives relate to E2 instances. A Potential solution is to identify these constructs with declarative time spans. It seems that it is required a generalization of phenomenal vs declarative properties.
This issue remains pending.
Berlin, December 2016