Re: failure with RANGE-MIN-CARDINALITY

Thanks a lot :)

2005/12/15, Thomas Russ <[email protected]>:
>
> On Dec 13, 2005, at 5:31 PM, Xingzhi Pan wrote:
>
> > Hello,
> > My assignment to RANGE-MIN-CARDINALITY is effectless:
> > |= (defconcept Person)
> >
> > |c|PERSON
> >
> > |= (defrelation rel ((?p1 Person)(?p2 Person)))
> >
> > |r|REL
> >
> > |= (retrieve all ?x (RANGE-MIN-CARDINALITY rel Person ?x))
> >
> > Processing check-types agenda...
> > There is 1 solution:
> >   #1: ?X=0
> >
> > |= (assert (RANGE-MIN-CARDINALITY rel Person 1))
> >
> > |P|(= (RANGE-MIN-CARDINALITY REL PERSON) 1)
> >
> > |= (retrieve all ?x (RANGE-MIN-CARDINALITY rel Person ?x))
> >
> > There is 1 solution:
> >   #1: ?X=0
>
> This is a bug in the released version of PowerLoom.  It has been fixed
> in newer versions, but we haven't yet had the time to put a release
> together.
>
> In the meantime, you can achieve the effect you want by making the
> assertion to the relation
>
>    RANGE-CARDINALITY-LOWER-BOUND
>
> instead:
>
>    (assert (range-cardinality-lower-bound rel person 1))
>
> Just to amplify on the modeling a little bit.  RANGE-MIN-CARDINALITY and
> RANGE-MAX-CARDINALITY are functions and thus can only have a single
> value.
> RANGE-CARDINALITY-LOWER-BOUND and RANGE-CARDINALITY-UPPER-BOUND are
> relations
> and can have multiple assertions made about them.   Through inference
> they
> influence the value of RANGE-MIN-CARDINALITY and RANGE-MAX-CARDINALITY,
> which will take the greatest lower and least upper bound respectively.
>
> By the way, I don't think you are getting the meaning that you
> may be expecting from the assertion
>
>    (assert (RANGE-MIN-CARDINALITY rel Person 1))
>
> This says that the CONCEPT Person has at least one REL.  It does NOT
> say that instances of Person have at least one REL, and since the
> definition REL says it applies to instances of Person instead of
> Concept, I don't think this is what you want.  I suspect that you
> really want to have a rule like
>
>    (assert (=> (person ?p) (range-cardinality-lower-bound rel ?p 1)))
>
> which says all persons have at least 1 rel.  You can conveniently
> include
> this rule in the definition of Person like:
>
> (defconcept person (?p)
>     :=>  (range-cardinality-lower-bound rel ?p 1))
>
>
> >
> > But RANGE-MAX-CARDINALITY DID work as I've expected. Anyone has ideas
> > about this? Thanks a lot.
> >
> > --
> > Pan Xingzhi
> > _______________________________________________
> > powerloom-forum mailing list
> > [email protected]
> > http://mailman.isi.edu/mailman/listinfo/powerloom-forum
>
>


--
Pan Xingzhi