[tcs-lc] difference between IsParentOf/IsChildOf; and Includes/IsIncludedIn RelationshipTypes?

[Richard Pyle]

Hi Jessie,

Many thanks for the very helpful responses to all of my "issues"!  I agree
that we should keep the email threads clearly separated, and I apologize for
mixing topics in a single message.

I'll think about these different issues in the context of your replies, and
respond separately on each, as needed.  For now, I only have one follow-up
reply:

> > 3) What is the difference between IsParentOf/IsChildOf; and
> > Includes/IsIncludedIn RelationshipTypes?
> > Several times during the earlier TCS/LC email exchanges, I asked for
> > someone
> > to distinguish between the following statements:
> >   1) ConceptA is Parent of Concept B
> >   2) ConceptA includes ConceptB
>
> The difference between these 2 types of relationships is that the
parent/child
> relationship is parent taxon of and child taxon of and is meant to
represent
> the relationships defined by a taxonomist when doing a revision. i.e. the
> relationships are as defined by one taxonomist for one classification.
i.e.
> vertical relationships within a classification
>
> The includes/included in is to capture the equivalence between two
concepts in
> different classifications or revisions, i.e. horizontal relationships
between
> classifications.

A couple more stuffs:

1) Does this mean that parent/child relationships should only be used when
Relationship/ToTaxonConcept points to a Concept with the *same* AccordingTo
as the current TaxonConcept, and includes/excludes relationships should only
be used when Relationship/ToTaxonConcept points to a Concept with a
*different* AccordingTo?  Are there any exceptions to either of these?

2) The distinction between "horizontal" and "vertical" is a bit squishy, if
you are defining these in terms of specific taxonomic ranks.  So-called
"horizontal" Relationships between different classifications could indeed
traverse ranks.  Or, is "vertical" defined simply as "Within a single
classification", and "horizontal" as "between two different
classifications"?

> Clearly one could think of parent child as includes/included but the
intention
> was to be within and between classification comparison, which seemed to be
> different to us when modelling. One is about building the classification
and
> the other is about comparing classifications. Hope this explains this
point
> and you agree we need both.

I don't necesarily agree we need both (pending the answer to my question #1
above), except as a performance enhancement device to save the processing
time required to compare "AccordingTo"s of two TaxonConcet instances linked
by a Relationship of Type "includes/included in".  This is complicated
further by the "has synonym" RelationshipType.  In any case, clearly a point
of discussion that exceeds the definition of "minor".

A related question, though:  would one ever use parent/child
RelationshipAssertion types? By your explanation above, I'm assuming not.

Thanks again for the clarifications.

Aloha,
Rich

P.S. After re-reading Roger's excellent UserGuide just now, I understand why
"IsLaterHomonym" is used instead of "IsJuniorHomonym".  I also have a number
of other issues prompted by my re-reading of the User Guide, but none of
them would fall into "minor" category, so I'll defer discussion to a later
time.