Dear all, This is not a part of the discussion in April about groups and aggregations. It is groups as a way to model relations between persons (actors). I gave a presentation about CRM and prosopography at the DH2014 workshop "Ontologies for prosopography" (see http://edd.uio.no/artiklar/DH2014/C-E_Ore_prosopography.pdf ).
The current CRM way to model relations between persons is to use the E74 Group. A relation is modeled as an instance of E74 Group and the type of relation is expressed via P2 has Type. In a non-symmetric relation each person is linked via 'P107 is current or former member of ' specified by 'P107.1 kind of member'. This is all according to the scope note in CRM. One may note that an instance of E74 Group used in this way represents an instance, an n-tuple, of a relation (seen as a set of n-tuples as in mathematics or in relational databases). The relation is identified by the type of the E74 group. I was a little skeptical when this way of modeling relations where introduced in CRM. My first thought was to define explicit, typed properties. After studying how for example the SNAP (Standards for Networking Ancient Prosopographies, http://snapdrgn.net/) tries to cope with their at least 65 identified relations between persons by introducing a relation class in RDFS, I realized that the CRM solution is very good. Since this is not meant to be a statement about me and CRM, I will raise two issues which I think need some discussion. 1) E74 Group scope note "This class comprises any gatherings or organizations of two or more people that act collectively or in a similar way due to any form of unifying relationship.[...]" Will all related persons fulfill the requirement " act collectively or in a similar way due to any form of unifying relationship", that is, is E74 Group too narrow to be used to model all kind of relations between persons like the ones we find in prosopography? 2) The modeling of relations by 'P107 is current or former member of ' specified by 'P107.1 kind of member': If this is to be implemented in RDF(S), should we in the CRM definition recommend or at list hint to a good solution to implement the .1 E55 Type properties? Regards, Christian-Emil
