Improve class and property definitions

[VladimirAlexiev]

See Guidelines for writing definitions in ontologies

• definiendum: the thing being defined
• definiens: the definition, which (following Aristotle) should consist of:
  • genus (genus proximus): the superordinate concept (superclass)
  • differentia: distinguishing features

The paper gives lots of useful advice, in particular:

• the thing being defined should not be included in the definition, i.e. remove parasitic words from descriptions
  • eg "The event type AssociationEvent describes the association or disassociation..."
  • Is better shortened to "Association or disassociation..."
• the definition should not be circular
• the definition should give necessary and sufficient conditions, not just examples

I don't want to be anal about the way definitions are written, but in order to define EPCIS RDF classes (and some EPCIS props) in a reasonable way, we need to be very strict about what are we talking about.

The reason is that the EPCIS XML (and JSON) representations are data centric, which influences the design of RDF classes and props. Please see Ontological Realism as a Methodology for Coordinated Evolution of Scientific Ontologies, which says

• an ontology should be analogous not to a data model, but rather to a reality model
• ontological realism positions the resulting ontologies as best candidates for serving as common models of all the data sources within a complex information ecosystem
• realist ontologies enable cross-enterprise-wide data integration by removing a layer of perspective from each of the several data sources involved

[CraigRe]

This topic is "nice to have" and deferred to the next EPCIS revision.