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Re: ISSUE-111 Proposal to Resolve

From: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Date: Tue, 19 Aug 2008 16:48:28 +0100
Message-Id: <BC57CB25-C9A6-4515-9D46-63159D193C62@comlab.ox.ac.uk>
Cc: Bijan Parsia <bparsia@cs.man.ac.uk>, public-owl-wg Group WG <public-owl-wg@w3.org>
To: Jim Hendler <hendler@cs.rpi.edu>


I'm not trying to force you to agree to anything, nor do I  
"disagree", nor am I "involved" in the issue in the sense that I have  
an axe to grind -- as far as I am concerned closing with no action  
would be just fine, but at the F2F the sameAs^3 idea was proposed as  
a compromise.

What I have been trying to do is to push the issue towards resolution  
(something that I believe is completely consistent with my chair  
role) by getting you to explain more clearly what your objection is  
and how you would like the issue to be resolved. The first has  
started to become a little more clear, but the second is still *very*  


wanted to have at least

On 19 Aug 2008, at 14:44, Jim Hendler wrote:

> Ian - sameAs^3, if made "THE" thing to use would solve the problem,  
> it would just be very counterintuitive to real users -- I see no  
> advantage over adding some small semantics free declarative to OWL  
> Full documents (and remember it is only OWL Full) - and, I'm sorry,  
> maybe you see me as being unreasonable, but I simply don't see any  
> way I can sign on to the current proposal  --  Look, let me put it  
> this way - you will not convince my organization that the sameAs^3  
> solution (esp. as curently set up where any error signals an  
> intent) is a good one. We can go back and forth as much as you  
> want, but my organization won't agree to the current closing text
>  I know you don't like discussion of W3C process, but basically,  
> going back and forth on this won't get us anywhere, you and I  
> simply disagree - since you're involved in the discussion, Alan  
> should either schedule a vote or propose an alternative and then we  
> can move on - not every WG member needs to agree with everything,  
> and I've stated my objection for the WG to consider so I've been  
> treated fairly
>  -JH
> On Aug 18, 2008, at 4:13 PM, Ian Horrocks wrote:
>> On 18 Aug 2008, at 17:04, Jim Hendler wrote:
>>> Bijan,
>>> It is absolutely true as you say that if it is in OWL Full then  
>>> it is in OWL Full (you said it better), but the key here is we're  
>>> talking about when the user explicitly wants to signal that it  
>>> should be OWL Full -- seems to me having a very specific thing,  
>>> easy to find, in this particlar (and probably rare) case would  
>>> make everyone's lives easier -- I don't understand the  
>>> reluctance, I've looked at the discussion in the f2f, and it  
>>> seems to mainly concern general issues with signaling intent,  
>>> which I mostly agree with, the problem is this one specific case  
>>> - and why can't we just have some little piece of syntax, which  
>>> is only in OWL Full, which basically says "Don't expect complete/ 
>>> sound reasoning if you use me with an OWL DL tool" - seems to me  
>>> we could do something more mnemonic that sameas Sameas sameAs --  
>>> and would make things easier for both implementors and users
>> sameAs^3 seems to do exactly what you want without the need to  
>> introduce any new OWL RDF vocabulary, and it is at least easy to  
>> remember (even if not mnemonic). I'm open to suggestions, though,  
>> as to some other piece of OWL Full that could be used for the same  
>> purpose -- but remember that one of the criteria is that it should  
>> be vacuous (i.e., be entailed by every OWL Full ontology).
>> Ian
>>> Guess what I'm trying to ask is what would be the downside?  I  
>>> can only see positive advantages as an implementor
>>> -JH
>>> On Aug 18, 2008, at 10:48 AM, Bijan Parsia wrote:
>>>> On 12 Aug 2008, at 13:10, Jim Hendler wrote:
>>>>> OK, so supposing I'm an OWL DL user and I want to use a DL  
>>>>> reasoner.  I accidently, however, assert something that puts  
>>>>> the ontology in Full (and when we did the analysis of 1500  
>>>>> ontologies 3 years ago, there were at least 100 for which this  
>>>>> case was true -- usually because someone referred to something  
>>>>> from a remote name space without adding the appropriate type or  
>>>>> imported something that put them into Full without their  
>>>>> realizing it) -- so according to this, tools like Pellet,  
>>>>> instead of "fixing" these mistakes (heuristically) would now  
>>>>> need to assume the person knew what they were doing and that  
>>>>> they want to be in Full
>>>> No. If an ontology is syntactically in OWL Full it is in OWL  
>>>> Full. This has *always* been true.
>>>> How to *handle* OWL Full ontologies remains, as it was then, up  
>>>> to the tool. Pellet performs an analysis and repair phase with  
>>>> reports back on the repairs performed and a strict mode. Nothing  
>>>> would change with that.
>>>>> -- so it would be rare that they want to do this on purpose,  
>>>>> but not rare that it would happen by accident.
>>>>> My point is not that I think there shoudln't be some way to do  
>>>>> this, but rather that it should be explicit -- otherwise we get  
>>>>> in a situation where tools will assume it's a mistake, and then  
>>>>> the user will have to do something extra to make it clear they  
>>>>> meant it
>>>>> So my argument is not that we should have some way to always  
>>>>> signal intended use, but that for this corner case, we should  
>>>>> have something unambiguous that is not likely to be used by  
>>>>> mistake (which is why, sameAs sameAs sameAs seems appealing)
>>>> I think if we give advice and follow that advice up with tools  
>>>> support (e.g., in the report say, "This ontology is OWL Full  
>>>> only in virtue of the notorious sameAs^3 triple which generally  
>>>> means that this is intended to be owl full. This reasoner does  
>>>> not support OWL Full semantics, would you like the (sound but  
>>>> incomplete wrt subusmption) OWL DL results anyway?"
>>>> Cheers,
>>>> Bijan.
>>> "If we knew what we were doing, it wouldn't be called research,  
>>> would it?." - Albert Einstein
>>> Prof James Hendler				http://www.cs.rpi.edu/~hendler
>>> Tetherless World Constellation Chair
>>> Computer Science Dept
>>> Rensselaer Polytechnic Institute, Troy NY 12180
> "If we knew what we were doing, it wouldn't be called research,  
> would it?." - Albert Einstein
> Prof James Hendler				http://www.cs.rpi.edu/~hendler
> Tetherless World Constellation Chair
> Computer Science Dept
> Rensselaer Polytechnic Institute, Troy NY 12180
Received on Tuesday, 19 August 2008 15:49:12 UTC

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