Friday, March 03, 2006
Generative Methodology Glass Bead Games
On the limits of the OWL standard à [184]
Reading material [1]
Reading material [2]
Reading material [3]
Summary of the discussion up to this point à [186]
On ontological modeling of expression
Subtitle: copying an individual between ontologies
On Formal verses Natural systems à [206]
Communication from Andrea Proli
Hello Paul,
I have very short time to answer, so, just a quick feedback. You are right when you say:
"I conjecture that the specific issue faced by the BioPAX 'physicalEntityParticipant' class, is that
description logics ARE NOT OPEN to the
conversion of instances to classes. This is why I call the so called open world assumption of DL, a
partial open world assumption."
Description Logics always consider so-called TBoxes (i.e. the set of class definitions and class-subclass relationships constituting the "schema") to be sharply separated from ABoxes (descriptions of instances, also called "individuals" or "objects" - I would not use the term "reifications of classes" in this context, because "reification" has a more frequent use to denote quite a different thing in DLs, OO modelling, and RDF-based languages).
Together, an ABox and a TBox form what is called a "Knowledge Base" in the DL context. In a sense, such a separation between "schema" and "instance", also referred to as the separation between "intension" and "extension", actually makes DLs only partially open, as you state.
However, I would not extend your "partial unopenness" claim also against OWL *in general*, because OWL-Full allows classes to be treated as instances and vice versa, and also allows classes to be treated as properties and vice versa (although OWL-DL does not - this is the tradeoff between "expressivity" and "decidability").
I will try and make an extended answer as soon as I have time. Thank you and sorry for being short, see you soon on Groove.
Andrea