- From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
- Date: Thu, 5 Mar 2009 22:34:33 +0000
- To: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Cc: boris.motik@comlab.ox.ac.uk, public-owl-wg@w3.org
Looks good to me too. Ian On 5 Mar 2009, at 13:19, Peter F. Patel-Schneider wrote: > Aside from a simple typo - a:equivalentClass - this looks great. > > I've also spec'd the needed changes to the Manchester Syntax and its > document. No problems there either. > > peter > > > From: "Boris Motik" <boris.motik@comlab.ox.ac.uk> > Subject: A description of the changes necessary to implement named > data ranges > Date: Thu, 5 Mar 2009 12:28:19 -0000 > >> Hello, >> >> Here is a description of how the named data range extension would >> work. In >> short, we'd introduce a new type of axioms called >> DatatypeDefinition. These >> would allow you to define a datatype as having some built-in >> value. Then, you >> would be able to write something like this: >> >> (1) Declaration( Datatype( a:myDT ) ) >> (2) DatatypeDefinition( a:myDT DatatypeRestriction >> ( xsd:integer ... ) ) >> >> Note that (1) is necessary because without it, axiom (2) alone >> would invalidate >> the typing constraints (it would use a URI that is not properly >> typed). These >> axioms would be mapped into RDF into (3) and (4), respectively: >> >> (3) a:myDT rdf:type rdfs:Datatype >> (4) a:myDT a:equivalentClass ... >> >> >> We would call datatypes occurring in such axioms '''defined'''. To >> obtain a >> logic with favorable computational properties, in OWL 2 DL we'd >> have the >> following conditions: >> >> - If the axiom closure contains a datatype declaration, then the >> datatype MUST >> be in the datatype map or the axiom closure MUST contain a >> datatype definition >> for the datatype. >> >> - A datatype definition axiom MUST NOT define a datatype that is >> in the datatype >> map. >> >> - Datatype definitions MUST be acyclic. >> >> - Datatype restrictions MUST involve only datatypes from the >> datatype map - that >> is, the datatypes defined through datatype definition axioms have >> no facets. >> >> >> >> All these changes would be reflected in the Syntax document. The >> impact to all >> other documents would be quite small: >> >> - Changes to RDF Mapping are minimal and involve mapping the new >> axiom (into RDF >> and back); both changes are minimal. >> >> - Changes to Direct Semantics are minimal and involve defining the >> semantics of >> the new axiom. >> >> - Changes to the XML Syntax are minimal and involve adding a new >> axiom. >> >> - There are no changes to the RDF-Based Semantics. >> >> Regards, >> >> Boris >> >> >
Received on Thursday, 5 March 2009 23:28:03 UTC