[Bioperl-l] parent <-> subject etc

[Lincoln Stein]

A little late for me to chime in here, I know, but I would avoid "child" and 
"parent" terms because they imply a directionality that is appropriate for 
some, but not all, relationships.  Same for target and source.

(subject,predicate,object) is nicely neutral and accepted in the ontology 
community.  For the uninitiated, (subject,relationship type,object) is easier 
to understand.

Lincoln


On Wednesday 19 March 2003 04:04 pm, Chris Mungall wrote:
> On Wed, 19 Mar 2003, Hilmar Lapp wrote:
> > There are different names around for the triple (actually, a quadruple
> > with the namespace) making up the relationship between two vertices:
> >
> > 	(subject,predicate,object)
> >
> > or
> >
> > 	(child,relationship type,parent)
> >
> > or
> >
> > 	(target,relationship type,source)
> >
> > Some people have expressed in the past that some of these depictions
> > are inferior to others for some reason or another, which quite frankly
> > I don't agree with (e.g., subject/predicate/object may make a lot of
> > sense for ontology terms, but not really for feature graphs). To me
>
> for containment graphs or is-a inheritance graphs, the semantics of
> 'parent' vs 'child' is obvious, but this is not the case for other kinds
> of graph. using subject/object there is no potential for ambiguity.
>
> > it's mostly a matter of taste, consistency, and documentation to make
> > sure the directionality doesn't get confused (feature graphs,
> > bioentry-bioentry relationships, and term-term relationships are all
> > directed).
> >
> > So, just to be sure I'm not confused already, if I define that the last
> > (3rd) element in the aforementioned tuples has the smaller distance to
> > the root along the 1st element's path to the root, then the order of
> > elements above depicts the equivalent designations, right?
>
> if you're asking if they are all equivalent, yes. ie child=subject
>
> i think it's wrong to thing in terms of graphs that are always rooted -
> what about cyclical graphs?
>
> > Once we all agree on this I'll document it in RelationshipI and the
> > biosql schema.
> >
> > 	-hilmar
>
> _______________________________________________
> Bioperl-l mailing list
> Bioperl-l at bioperl.org
> http://bioperl.org/mailman/listinfo/bioperl-l

-- 
========================================================================
Lincoln D. Stein                           Cold Spring Harbor Laboratory
lstein at cshl.org			                  Cold Spring Harbor, NY
========================================================================