Re: LANG: Defn of DL in Mappings

From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: LANG: Defn of DL in Mappings
Date: Tue, 31 Dec 2002 09:24:14 -0500

> >
> >>  ====
> >>
> >>  Bother, 2(b) doesn't do as much as I wanted for solving the inability to use
> >>  a bnode in two places problem, ... I think the abstarct syntax could benefit
> >>  from the following change:
> >>
> >>  In many places (to be defined precisely which)
> >>  replace
> >>    <URI reference>
> >>  with
> >>    <OWL Name>
> >>
> >>  and add a rule
> >>
> >>  <OWL Name> ::= <URI Reference>
> >>  <OWL Name> ::= <local identifier>
> >>
> >>  The latter play the same role in the abstract syntax as Blank node
> >>  identifiers play in N-triples and RDF/XML. (Note there are no blank node
> >>  identifiers in the RDF graph).
> >
> >This will not be done.
> >
> >>  This when combined with 2(b) allows near-arbitrary use of blank nodes while
> >>  clearly remaining within the constraints of the abstract syntax.
> >>
> >>  Jeremy
> >
> >peter
> 
> 
> Peter - is there a reason you say "this will not be done"?  I kind of 
> like Jeremy's proposal - if it doesn't break OWL DL on some formal 
> level, it seems like a good change - why don't you like it?

Because loops in descriptions can easily break OWL/DL.  Determining the
constraints under which this will happen is, in my expert opinion, a
difficult task that will, even if done correctly, produce no benefits.

peter