[Crm-sig] Symmetry of P130 and P139

Maximilian Schich maximilian at schich.info
Thu Mar 31 22:30:54 EEST 2011

Dear Martin, Martin, and all,

This is may be in contradiction with CIDOC philosophy, but might help to 
solve the issue:

Similarity and Derivation:
Practically, it does not make sense to put "similarity" and "derivation" 
into the same property. In real data there are up to two orders of 
magnitude more instances for "similarity", than for any form of 
"derivation" (See for e.g. 
http://revealingmatrices.schich.info/fig/7/Document-Monument.htm vs. 
http://revealingmatrices.schich.info/fig/7/Document-Document.htm ).

For a basic understanding of the difference between similarity and 
derivation see also George Kubler: The Shape of Time. 1962 including 
Oystein Ore's note 3 on p. 33 (cf. Schich 2009* pp 156-158).

As "similarity" usually works "across given criteria" - for e.g. two 
drawings being similar  using the same technique, or showing the same 
monument - similarity data should be represented and collected as a 
bi-partite classification network, with similar objects on one side and 
similarity criteria on the other (See Schich 2009* pp. 38-52). P130 does 
not allow for such a model, as it only establishes a relationship 
between two similar objects.

Derivation is best modelled as a directed network, either shortcut with 
simple links (P130/P139) or with "derivation events" between two objects 
dependent on each other.

In derivation data in general, it often makes sense to specify "unknown 
archetype" instances - otherwise curators have to introduce n*(n-1) 
"parallel copy" or "similarity" links in addition to all possible 
"derivative/influence" relationships back and forth the affiliation tree 
- which is crazy and therefore either almost never happens or carries a 
two digit error rate on behalf of database curators (See Schich 2009* 
pp. 53-57).

Influence vs. Citation:
For practical reasons, the link between archetype and derivative work 
should always point to the past - i.e. CIDOC should recommend P130, not 
P139 (see Baxandall 1985 "Patterns of Intention" s.v. "Excursus against 

* Schich 2009 see 

Best regards,

Dr. Maximilian Schich
DFG Visiting Research Scientist
CCNR - BarabásiLab | Northeastern University, Physics Dept.
110 Forsyth St., 111 Dana Research Center | Boston, MA 02115
tel.: +1 (617) 817-7880 | skype: maximilian.schich
mail: maximilian at schich.info | home: www.schich.info

Am 31.03.11 13:13, schrieb Martin Scholz:
> Dear All,
> the scope notes of P130 and P139 are as follows:
> P130:
> This property generalises the notions of "copy of" and "similar to" into a
> dynamic, asymmetric relationship, where the domain expresses the derivative, if
> such a direction can be established. Otherwise, the relationship is symmetric.
> It is a short-cut of P15 was influenced by (influenced) in a creation or
> production, if such a reason for the similarity can be verified. Moreover it
> expresses similarity in cases that can be stated between two objects only,
> without historical knowledge about its reasons.
> P139:
> This property establishes a relationship of equivalence between two instances of
> E41 Appellation independent from any item identified by them. It is a dynamic
> asymmetric relationship, where the range expresses the derivative, if such a
> direction can be established. Otherwise, the relationship is symmetric. The
> relationship is not transitive. The equivalence applies to all cases of use of
> an instance of E41 Appellation. Multiple names assigned to an object, which are
> not equivalent for all things identified with a specific instance of E41
> Appellation, should be modelled as repeated values of P1 is identified by
> identifies). P139.1 has type allows the type of derivation, such as
> "transliteration from Latin 1 to ASCII” be refined..
> Both scope notes state that the properties are dynamic asymmetric, i.e. may be
> both symmetric and asymmetric, depending on the type of relation the property
> instances resemble.
> This is misleading and calls for clarification, as
> a) the term dynamic asymmetric relation is not defined
> b) from a mathematical/logical point of view, a relation may not be both
> symmetric and asymmetric. (but it may be neither sym. nor asym.!)
> Furthermore, P130 defines an inverse property while P139 does not. This is
> inconsistent. If both properties are regarded as symmetric, the inverse of P130
> should be removed. If both are not symmetric, an inverse should be added to P139.
> A solution could be to define P130 and P139 as not symmetric and include inverse
> properties for both. If symmetric properties are needed, new (sub)properties of
> P130 and P139 need to be introduced which are then marked as symmetric and
> without inverses.
> Kind regards
> Martin Scholz

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