- From: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>
- Date: Thu, 18 Apr 2002 15:49:09 +0200
- To: www-webont-wg@w3.org
I must apologise for not getting the discussion on the definition of the compliance levels off the ground last week (if you look at the CfP for ECAI'02 you will know why). I must also apologise for not being on tonight's teleconf, because I'm on a train back from Germany (the joys of European projects!) To give at least an initial move on my action item, below I: - summarise the current status - identify a few groups of language features that "go together" - propose a number of potential layerings derived from these groups. Given the time pressure, this has not been discussed in the task-force on this action item, and is simply written in my own name. Frank. ---- CURRENT SITUATION Until now, we've seen the following proposals: [a] "original proposal": original proposal by Ian, Peter and me at [1] A variant of this was to move all the cardinalities into level 1. This move was uncontroversial, so I will take that as read. It was felt that this proposal did not contain many often used constructions from level 2. [b] "top heavy proposal": Everything is in level 1, except arbitrary combinations of boolean expressions. (This was on the board after a public auction session at the F2F) Suggested name: "farcical level 2" (since there was wide agreement that this resulted in a level 2 not worth wanting) GROUPS OF LANGUAGE FEATURES In what follows I try to get away from the "item by item" discussion by grouping some of the language features, and propose a few levelling-options. One extreme interpretation of this proposal is to take >*all*< of these as separate levels (I wouldn't be unsympathetic to this, by the way). Another one is of course to join some of these. GROUPS OF LANGUAGE FEATURES: I propose the following groups of features, each with a name for use in the discussion: - RDF Schema stuff - (In)equality - Property characteristics - Framy stuff: - Full booleans & class expressions: as follows: RDF Schema stuff (using only classID's ("named classes") as arguments) primitiveclass subClassOf subpropertyof domain range Property named & unnamed Individual (In)equality sameClassAs(<classID>) samePropertyAs sameIndividualAs differentIndividualAs Property characteristics inversOf transitive symmetric Named class stuff (where classes appear in the expressions using classID's only ("named classes"), ie. not arbitrary <definition>'s) extra class-defining constructs definedclass enumeratedclass slot constructs range, optional/required singlevalued/multivalued required range/value cardinality constructs cardinality mincardinality maxcardinality singlevaluedproperty uniquelyidentifying property Booleans & class expressions: (allow arbitrary <definition>'s for the following:) primitiveclass definedclass sameclassas subclass domain range boolean combinations disjoint [note: change to Disjoint( <definition> {,<definition>>} ) ] unionOf intersectionOf complementOf POSSIBLE LAYERS Possible layers would be - Level: RDF Schema - Level: RDF Schema plus (in)equality (often requested by implementors in the DAML programme) - Level: RDF Schema on steroids: RDF Schema plus (in)equality and property characteristics - Level: The old "original proposal" Favourable reactions were received on this as a layer (with the cardinalities thrown in). As Guus has shown, this is close to UML. - Level: Full languag: add booleans & class expressions This provides a number of possibilities: all of these separate layers, or some mergers among the above. Frank. ---- [1] http://www.cs.vu.nl/~frankh/spool/OWL-first-proposal/frame-annotated.html
Received on Thursday, 18 April 2002 09:51:47 UTC