Issue 499: Change the cardinality of P160

ID: 
499
Starting Date: 
2020-06-26
Working Group: 
3
Status: 
Open
Background: 

On virtual meeting of CIDOC CRM editorial team for version 7.0  on 2/6/2020 

The editorial team reviewed the  decision of the 46th sig meeting on issue 483 during the next virtual meeting and proposed 

(a) to NOT delete the following paragraph
"Consequently, an instance of E4 Period may occupy a number of disjoint spacetime volumes, however there must not be a discontinuity in the timespan covered by these spacetime volumes. This means that an instance of E4 Period must be contiguous in time. If it has ended in all areas, it has ended as a whole. However, it may end in one area before another, such as in the Polynesian migration, and it continues as long as it is ongoing in at least one area"
(b) to change the cardinality of the temporal projection property of STV → P160 [it’s one to one and has to change]

The crm-sig on 26/2/2020 accepted  the above (a) & (b)

June 2020

Current Proposal: 

Posted by Martin on 23/07/2020

Dear All,

I'd like to add the reasoning about the following in issue 499:

There was a question in the 46th meeting in Athens if the following paragraph in scope note of P4 Period

"Consequently, an instance of E4 Period may occupy a number of disjoint spacetime volumes, however there must not be a discontinuity in the timespan covered by these spacetime volumes. This means that an instance of E4 Period must be contiguous in time. If it has ended in all areas, it has ended as a whole. However, it may end in one area before another, such as in the Polynesian migration, and it continues as long as it is ongoing in at least one area"

is obsolete, because the scope note of E92 STV states:

"Intersections of instances of E92 Spacetime Volume, E53 Place and E52 Timespan are also regarded as instances of E92 Spacetime Volume. An instance of E92 Spacetime Volume is either contiguous or composed of a finite number of contiguous subsets."

However, if intersections of instances of E92 STV should be instances of E92 STV, contiguity in time will in general not be preserved.

Therefore the SIG decided on 26/2/2020

(a) to NOT delete the following paragraph

and to propose

(b) to change the cardinality of the temporal projection property of STV → P160 [it’s one to one and has to change]

The subset of instances of E92 STV which are instances of E4 Period by IsA, are however contiguous in time. Since intersections of E4 Period are not defined to be instances of E4 Period, there is no conflict that they are still instances of E92 STV.

Since E93 Presence can be described as intersections of a spatially unlimited, contiguous "time slice" of spacetime with an STV, instances of E93 Presence defined for instances of E4 Period or E18 Physical Thing are also contiguous in time.

Instances of E93 Presence defined for an STV not contiguous in time, may or may not be contiguous in time depending where it "cuts through".

Posted by Martin on 23/07/2020

...forgot:

therefore the equivalence of P160 with P4 from E4 Period downwards is valid with cardinality (1,1:0,n) and compatible with general cardinality of P160 (1,n:0,n).