Re: Expressing "not" in RDF rules

Sean B. Palmer wrote:

> Hi Norm,
>
> > If    :p :pointsTo :s
> > and   :p :pointsTo :t
> > and   not(s :pointsTo :t)
> > then  :p :hasEdge :t
>
> What you want is to say that there is no triple in the current store
> that fits the profile "_:s :pointsTo _:t". You can do that using
> log:notIncludes:-
>
>    { this log:notIncludes { [] :pointsTo [] } }
>      log:implies { :Test a :Success } .

Careful Sean, this is the N3 'extension' to RDF, not RDF 1. Perhaps you
might translate the above into proper RDF using the 1.0 XML syntax and you
will see what I mean.

The point is that simple logic formulas are not so simple in RDF (1.0) which
is targeted at simple assertional triples.

Jonathan