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Re: Proposal to close ISSUE-83 and ISSUE-8

From: Bijan Parsia <bparsia@cs.man.ac.uk>
Date: Thu, 10 Jan 2008 23:33:54 +0000
Message-Id: <69F1E735-2C33-4EA4-A744-09808F55C686@cs.man.ac.uk>
Cc: "Web Ontology Language ((OWL)) Working Group WG" <public-owl-wg@w3.org>
To: Jim Hendler <hendler@cs.rpi.edu>

On Jan 10, 2008, at 10:57 PM, Jim Hendler wrote:

> I must admit to being confused- I thought the issue of property  
> chains ending in data properties has the same decidability as  
> inversefunctional datatypes - that is, that Uli has a suggestion we  
> might adopt that fixes things (Bijan - you wailed on me when you  
> thought i was ignoring this!) -- is there a reason these are  
> different?  If not, shouldn't the solution work for Issue 8 as well?

The problem is that although decidable (though you have to be  
careful, so the exact details of the proposal matter) like *general*  
inversefunctional data properties, the implementation is seriously  
non-trivial and there has been no evidence that *any* implementor  
will implement it, at least, in a complete way. (This is why we have  
an "EasyKeys" proposal in the works.) So, we shouldn't *require* it  
as things stand now. However, if some implementor wants to implement  
it, or some user wants it and will pay some implementor, then they  
have syntax "ready to hand" (i.e., it doesn't require inventing new  
terms, just relaxing some restrictions on existing syntax).

Ah yes, you weren't at the F2F so you might not have the design  
principle I'm applying fresh to mind. At the first OWLED, the guiding  
principles for adding features were:
	1) There had to be strong, committed user demand. (i.e., it  
shouldn't just be "Nice to have I guess" but "I will use this")
	2) We had to have a good understanding of the feature, how to  
implement it, etc.
	3) We had to have commitment from the implementors to actually  
implement it.

At the moment there's not the slightest evidence that any implementor  
will implement this (the general feature).

What I believe some implementor *will* do is implement something  
similar to the corresponding DL-safe rules...but that's why we have a  
RIF task force.

Hence we close it until we get some evidence that it will be  
implemented. (The general feature, of course.)

>  -JH
> p.s. I was told this about issue 8, I cannot tell for sure if it  
> also is the case for issue-83,

Issue-83 proposes an undecidable feature.

Cheers,
Bijan.
Received on Thursday, 10 January 2008 23:34:13 GMT

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