- From: Bijan Parsia <bparsia@isr.umd.edu>
- Date: Fri, 4 Feb 2005 09:21:39 -0500
- To: Evren Sirin <evren@cs.umd.edu>
- Cc: "daml-process@bbn.com" <daml-process@bbn.com>, Daniel Elenius <elenius@csl.sri.com>, public-sws-ig@w3.org
On Feb 4, 2005, at 1:35 AM, Evren Sirin wrote: > Daniel Elenius wrote: [snip] >> > I have two concerns about this format: >> >> 1) Aren't all SWRL expressions supposed to be instances of the >> http://www.daml.org/rules/proposal/swrl.owl#Imp class? > > No, a SWRL expression body is supposed to be an AtomList which is > simply the conjunction of atoms in the list. By design. >> I know that this was the case in an intermediate >> version of OWL-S, but this version does not seem to be available >> anymore. Expressions were rules with >> empty heads (bodies?). > > I think at some point it was considered to use rules with empty > bodies. Then the expression would be written as the head of the rule. > SWRL defines empty body to be trivially true so the implication is > true whenever the head is true. But using rules in this way would be > more confusing so it was decided to use AtomList's directly. It's not just confusing, it's the wrong semantics, right? Precondtions *aren't* always true! >> 2) If this is not the case, i.e. we can use constructs from SWRL as >> we feel like it, > > No, we can not. [snip] Definitely not. The intention was that you'd use SWRL constructs in the relevant *ontologies*. So *outside* and expression, you can use SWRL rules as you see fit. Cheers, Bijan.
Received on Friday, 4 February 2005 14:22:57 UTC