[Crm-sig] issue 336 and spacetime volumes

Martin Doerr martin at ics.forth.gr
Wed Mar 20 15:19:44 EET 2019


Dear Christian-Emil,

I am not sure this is a good idea. Moving time-span properties onto E2 
just washes about the fact that the temporal projection of E2 and of E92 
are equivalent. If we make the paths more dissimilar, we just hide that 
there are two alternative ways to formulate it. If the formal rules of 
KR do not foresee the case, we just change the cardinality of P4 / P160 
to (1,1:0,n) or (1,1:0,2).

I am hesitating to propose a common superclass of E92 and E2 just to 
have one domain for P4/P160. It becomes an extremely abstract thing.

Opinions?

Best,

Martin


On 3/19/2019 1:19 PM, Christian-Emil Smith Ore wrote:
> Hi Dan, all
> The recommended way to model historical periods is as instances of E4 Period. This recommendation is older than the introduction of E92.
>
> The current model with E2 Temporal Entity, E52 Time-Span and E92 STV is not optimal and E92 is not the reason eventhough it is pretty abstract. In my opinion, E52 Time-Span is redundant and can be replaced by E2 Temporal Entity with an adjusted scope-note and change the domain of
>
> P79 beginning is qualified by: E62 String
> P80 end is qualified by: E62 String
> P81 ongoing throughout: E61 Time Primitive
> P82 at some time within: E61 Time Primitive
> P83 had at least duration (was minimum duration of): E54 Dimension
> P84 had at most duration (was maximum duration of): E54 Dimension
> P160 has  temporal projection
>
> P86 falls within (contains): E52 Time-Span can be replaced by P117 occurs during (includes): E2 Temporal Entity
>
> If E52 is removed the property P160 has temporal projection should be an injection into E2 and have the cardinality (1,1:0,1)
>
> (in any case: P78 is identified by (identifies) should be deprecated since E49 Time Appellation is already deprecated.)
>
> See also http://cidoc-crm.org/sites/default/files/issue%20326%20overview%20and%20thought.pptx for a graphical overview.
>
> Best,
> Christian-Emil
>
> ********
> E2 Temporal Entity:
> This class comprises all phenomena, such as the instances of E4 Periods, E5 Events and states, which happen over a limited extent in time.  This extent in time must be contiguous, i.e., without gaps.  In case the defining kinds of phenomena for an instance of E2 Temporal Entity cease to happen, and occur later again at another time, we regard that the former E2 Temporal Entity has ended and a new instance has come into existence. In more intuitive terms, the same event cannot happen twice.
>
> In some contexts, these are also called perdurants. This class is disjoint from E77 Persistent Item. This is an abstract class and has no direct instances. E2 Temporal Entity is specialized into E4 Period, which applies to a particular geographic area (defined with a greater or lesser degree of precision), and E3 Condition State, which applies to instances of E18 Physical Thing.
>
>
> *********
> E52 Time-span
> This class comprises abstract temporal extents, in the sense of Galilean physics, having a beginning, an end and a duration.
>
> Time Span has no other semantic connotations. Time-Spans are used to define the temporal extent of instances of E4 Period, E5 Event and any other phenomena valid for a certain time. An E52 Time-Span may be identified by one or more instances of E49 Time Appellation.
>
> Since our knowledge of history is imperfect, instances of E52 Time-Span can best be considered as approximations of the actual Time-Spans of temporal entities. The properties of E52 Time-Span are intended to allow these approximations to be expressed precisely.  An extreme case of approximation, might, for example, define an E52 Time-Span having unknown beginning, end and duration. Used as a common E52 Time-Span for two events, it would nevertheless define them as being simultaneous, even if nothing else was known.
>
> Automatic processing and querying of instances of E52 Time-Span is facilitated if data can be parsed into an E61 Time Primitive.
>
> *********
>
>
> ________________________________________
> From: Crm-sig <crm-sig-bounces at ics.forth.gr> on behalf of Dan Matei <danmatei50 at gmail.com>
> Sent: 19 March 2019 09:27
> To: crm-sig at ics.forth.gr
> Subject: Re: [Crm-sig] Space time volumes
>
> Hi fiends,
>
> On Mon, 18 Mar 2019 at 19:20, Martin Doerr <martin at ics.forth.gr> wrote:
>
>> Nevertheless, we used the term informally in the CRM. We could name E92 as "abstract".
> For me, some E92 are not abstract. E.g. I instantiate "Byzantine
> Period" (it is somwhat difficult to place it in South America :-) :
>
> <#ByzantinePeriod> <isA> <crm:E92_Spacetime_Volume>
> <#ByzantinePeriod> <crm:P160_has_temporal_projection> <330-1700>
> <#ByzantinePeriod> <crm:P161_has_spatial_projection> <#EsternEurope>
> <#ByzantinePeriod> <crm:P161_has_spatial_projection> <#Levant>
> <#ByzantinePeriod> <crm:P161_has_spatial_projection> <#NorthAfrica>
>
> Also:
>
> <#BronzeAge1> <isA> <crm:E92_Spacetime_Volume>
> <#BronzeAge1> <crm:P2 has_type> <#BronzeAge-Concept>
> <#BronzeAge1> <crm:P160_has_temporal_projection> <p?1>
> <#BronzeAge1><crm:P161_has_spatial_projection> <#JapaneseIslands>
>
> <#BronzeAge2> <isA> <crm:E92_Spacetime_Volume>
> <#BronzeAge2> <crm:P2 has_type> <#BronzeAge-Concept>
> <#BronzeAge2> <crm:P160_has_temporal_projection> <p?2>
> <#BronzeAge2><crm:P161_has_spatial_projection> <#Scandinavia>
>
> Should I worry ?
>
> Dan
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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)
                   
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