Re: Fragments discussion, continued

On DL-Lite

Jim Hendler wrote:
> telecon) - so those have both been motivated.  You've suggested another 
> fragment move Rec track, and all I'm asking is whether you can motivate 
> it on the same dimensions that the others were.

I think on the telecon we had a view that the fewer rec-track fragments 
the better, but we need to rec-track those fragments where we expect 
there to be a genuine need for interoperability between commercial 
systems. I think Bijan characterized this as a CR exit criteria to do 
with two 'production quality' implementations targetting that fragment.

I personally would prefer if Jim could state an opposition to DL-Lite in 
a constructive tone of - if at the end of CR we have N implementations 
of DL-Lite that have properties A, B and C then DL-Lite is a worthwhile 
recommendation, otherwise not.

I think the point has been made that since an OWL DL implementation is a 
DL-Lite implementation, to be meaningful at least some of the properties 
A, B and C have to be ones that a non-optimized DL implementation would 
not meet. e.g. it could be a complexity measure.

In a sense, the DL-Lite advocates should be outlining such properties, 
which would help articulate why the fragment is useful. The bumper 
sticker seems to be "scalable A-Box reasoning" so turn that into an 
objective measure that can be checked at CR.

(We could have tests with substantial A-Box and the CR exit criteria for 
DL-Lite is that the DL-Lite implementations should be significantly 
faster than the DL implementations)

I hope that we can be serious about taking fragments to CR while being 
neutral about whether they end in Rec or WG Note - either state being 
satisfactory - the difference being about the level of real interest 
exhibited during CR

Jeremy