Re: (DQL) Expressiveness of Query Patterns

From: Richard Fikes (fikes@ksl.stanford.edu)
Date: 12/04/01


> >We indeed will need to add on capabilities for "immediate superclass of
> >a class", "numbers of different answers", etc.  I am becoming
> >increasingly concerned that we do not have agreement on even the basics
> >of DQL, and so I am focusing on one piece at a time.
> 
> Hmm, I don't like that strategy, as we never know quite what we are 
> agreeing to. Lets have the overall design sorted out first and then 
> get to the details.

I have sent out a proposed overall design.  You, in particular, seem to
have disagreed with most of it.  So, I was focusing on what I thought
were some core pieces of the design.

> >Well, there is an issue here of goals.  I am interested in designing a
> >query-answering language and protocol for DAML+OIL that will be
> >generally useful for the Semantic Web.  Almost no one outside the KR&R
> >community cares about logical completeness or tractability in most
> >cases.
> 
> OK, you are stating a different agenda (and one that I am myself 
> sympathetic to) but it really is a DIFFERENT agenda than the one that 
> has driven DAML+OIL so far. I worry that the resulting language is 
> going to be a mixture of incoherent fragments driven by different, 
> and divergent, agendas. I would prefer DAML+OIL development to be 
> continued in the DL tradition, and if the WebOnt initiative feels 
> that some other approach should be adopted, perhaps as an 
> alternative, then another, different, intiative be begun to 
> investigate that.

Well, if the committee also feels that way, then indeed perhaps we (or
I, at least) should move my efforts to design a query language for the
Semantic Web to WebOnt.  I think if this committee confines itself to
DL's, then it is at risk of losing its impact.  I thought that the
charter of this committee was to design the DAML language and that the
DAML language was to be a candidate standard semantic markup language
for the Semantic Web.  Using the DL tradition as the core of the DAML
language seems like a good idea and has resulted in a very elegant and
powerful core language.  However, it seems to me to be standing the
effort on its head to confine the further development of the language
and in this case the development of a query language for DAML to
concerns of the DL community.  I think the committee needs to continue
to lead in the development of Semantic Web language development and that
it would be a major mistake for the committee to hold on to decision
criteria that are not in the best interests of Semantic Web
development.  Such a position would indeed push the WebOnt initiative in
the direction of developing alternative approaches, which I think would
be extremely unfortunate for all of us who are invested in DAML
development.

> And 
> as for "logical completeness", I am not sure what you mean

By logical completeness, I mean guaranteed to find all the answers.  Not
all reasoners will be able to do so, and that shouldn't disqualify them
from being used.  

I am out of time for now.

Richard


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