W3C home > Mailing lists > Public > public-owl-wg@w3.org > August 2008

Re: ISSUE-111 Proposal to Resolve

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Tue, 19 Aug 2008 12:25:27 -0400
Message-Id: <328B534C-1377-4BC2-9E13-4FD960E3FA40@cs.rpi.edu>
To: Ian Horrocks <ian.horrocks@comlab.ox.ac.uk>
Cc: Bijan Parsia <bparsia@cs.man.ac.uk>, public-owl-wg Group WG <public-owl-wg@w3.org>

Ian, I apologize, I didn't mean to imply anything was wrong

I think by now you have seen my email with two possible ways forward - 
a specific "tag" or,my preference, a decision not to include any such  

Bijan, I don't agree it is just editorial since this whole discussion  
came up in response to an issue and we need to resolve to close that  
issue as a wg.

Sent from my iPhone

On Aug 19, 2008, at 11:48 AM, Ian Horrocks  
<ian.horrocks@comlab.ox.ac.uk> wrote:

> Jim,
> 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* unclear.
> Ian
> 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 16:26:44 UTC

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