[Crm-sig] HW issue 378 where to put notes

Martin Doerr martin at ics.forth.gr
Thu Jun 6 17:54:36 EEST 2019

Dear All,

Here my trial guideline:

Frequently scholars and scientists would like to express more detail 
about a particular relation (property) between two entities than the 
type of the property itself expresses. These may be more details about 
the respective role or attitudes or arguments about the reliability of 
the information. In order to formally attach notes to properties in the 
currently dominant knowledge representation languages, one needs to 
replace the property by an equivalent path with an intermediate, 
auxiliary entity. Even though this mechanism has been provided for the 
CRM as "property classes", it considerably increases the complexity of 
the model and the user interface and decreases the performance of 
respective databases. The details given are in most cases not relevant 
in order to filter a large set of data by it. In that case they are 
relevant for the receiving user, but not for querying, and hence can be 
better expressed in a textual note.

The question that arises, is where to put the note, if not to an 
intermediate entity: to the domain instance or the range instance of the 
respective property. This is often intuitively done in the opposite way 
it should be done.

For instance: "Building house X"(E12) - P4 was carried out by - "John 
Smith"(E21)- P3 has note: "in the role of designer" sound perfectly 
logical, but is wrong!

This is the effect of context-free propositions in KR. The user sees the 
local context, but the note is attached to the person, not to the 
building activity. The role however does not hold for the person at all 
times, but only for this person in this activity. If "John Smith" will 
have another role in another activity, the context of this role becomes 
ambiguous. Therefore, if a note is meant to describe a property, but is 
instead attached to either domain or range instance, it must contain, in 
textual form, the path to the other entity instance.

This leaves two choices for the above example:
"Building house X"(E12) - P4 was carried out by - "John Smith"(E21).
"Building house X"(E12) - P3 has note: "was carried out by John Smith in 
the role of designer"
"Building house X"(E12) - P4 was carried out by - "John Smith"(E21) P3 
has note: "performed Building house X in the role of designer"

Since the instance "Building house X"(E12) is actually the *context* for 
this role, or, in other terms, more specific to the property instance 
than the actor, the rule is to attach a note about a property to the 
more specific domain or range instance, as shown in choice A) in the 
above example, if the property is not going to be expanded by an 
intermediate entity. Then one has to repeat the missing path in the note 
as shown above.


  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
  Email:martin at ics.forth.gr   

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