- From: Tim Berners-Lee <timbl@w3.org>
 - Date: Tue, 6 Mar 2001 22:44:43 -0500
 - To: <jos.deroo.jd@belgium.agfa.com>, <connolly@w3.org>, <www-rdf-logic@w3.org>, "Sandro Hawke" <sandro@w3.org>
 
> > > [Dan Connolly writing:]
[...]
> > >                                                    If you make the
domain
> > > of :of and :and be :Sum (aka :Integer) and recall that = denotes
> > > daml:equivalentTo,
> > > you can write "the sum of 4 and 3 is 7" as
> > >   [ :of 4; :and 3 ] = 7.
>
> And without that qualification, this doesn't work.  Let's rename and
> avoid [] for clarity.  You're saying:
>
>     7 sum_of_2_part_1 4.
>     7 sum_of_2_part_2 3.
No, that's not what [] mean - (you can't just remove them!) they mean (in
this case)
    There exists x such that
         x sum_of_2_part_1 4.
         x sum_of_2_part_2 3.
         x num:equals 7 .
Tim
PS:
I wouldn't use daml:equivalent because 7 and a thing whose LHS is 2 and RHS
is 5 are different for the reasons you menation - you could deduce that 2+4
was 7.
    There exists x such that
         x sum_of_2_part_1 4.
         x sum_of_2_part_2 3.
        x daml:equiavlent 7 .
    There exists y such that
         y sum_of_2_part_1 2.
         y sum_of_2_part_2 5.
        x daml:equivalent 7 .
But
         x sum_of_2_part_2 3.
        x daml:equiavlent 7 .
imply
        7 sum_of_2_part_2 3
and similarly
        7 sum_of_2_part_2 4
and so on...
Received on Tuesday, 6 March 2001 22:45:01 UTC