W3C home > Mailing lists > Public > www-webont-wg@w3.org > June 2003

Fwd: daml:item

From: Jim Hendler <hendler@cs.umd.edu>
Date: Thu, 19 Jun 2003 18:04:38 -0400
Message-Id: <p05200f15bb17e2ac0ec6@[]>
To: webont <www-webont-wg@w3.org>

Bijan Parsia raised the issue of whether OWL should include something 
similar to the daml:item feature for compatibility.  We decided that 
this was handled under issue 5.5, by (essentially) passing the buck 
-- i.e. saying RDF Core decided to remove these and that we saw no 
reason to add an owl:item.   I discussed this with him, and he sent 
me the following - pointing out that while there is a work around, 
there is a case (putting restrictions on all members of a list) that 
is easier with daml:item.
  Does this present new information that tempts anyone to request 
re-opening of issue 5.5 and consideration of adding this feature?
p.s. please note that he uses a case from daml-s, and he is currently 
a member of the web services description WG, working on helping them 
with their need to produce a mapping to RDF (which he is proposing to 
do at least in part via OWL) using DAML-S, so this is more than a 
casual observation.

>Date: Thu, 19 Jun 2003 14:11:59 -0400
>Subject: daml:item
>From: Bijan Parsia <bparsia@isr.umd.edu>
>To: hendler@cs.umd.edu
>X-Spam-Status: No, hits=-9.5 required=5.0
>	autolearn=ham version=2.53
>X-Spam-Checker-Version: SpamAssassin 2.53 (
>One common use of daml:item is to make typed lists, say, a list that 
>can only contain ex:Person (this actually pops up quite a bit in 
>DAML-S). You put a restriction on daml:item to the desired class. 
>This is just syntactic sugar as it can be expressed as a pair of 
>restrictions on daml:first and daml:rest (or their rdf equivalents). 
>(Note, at one point I thought this wasn't true because of daml:nil, 
>but Peter claimed that daml:nil is compatible with every list type.) 
>I think there are probably other use cases, but don't have any off 
>So, DAML+OIL compatibility isn't merely a matter of deleting 
>daml:items. It's a feasible conversion, but it makes a lot of 
>authoring uglier and some modeling conceptually harder to explain.
Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
Univ of Maryland, College Park, MD 20742	  *** 240-277-3388 (Cell)
http://www.cs.umd.edu/users/hendler      *** NOTE CHANGED CELL NUMBER ***
Received on Thursday, 19 June 2003 18:04:43 UTC

This archive was generated by hypermail 2.4.0 : Friday, 17 January 2020 23:04:46 UTC