Thanks, Roger.

Yes, I was waiting for commentary on my use of "explicitly implied"....

"explicitly implied" is actually contradiction in terms:

Agreed -- but I couldn't think of a different term to express what I meant. Rather than grasping for alternate expressions, let me explain it with an example.

Suppose a book made clear and unambiguous references to "Ditrichum cornubicum Paton". And then, in the text account directly underneath, there is a paragraph that makes reference to "D. cornubicum". Because this has an abbreviated genus name, it is technically not the same character text-strings as "Ditrichum cornubicum". However, the contextual placement represents an "explicit implication" (oxymoron that it may be) that "D." is intended as an abbreviation of "Ditrichum". It is "explicit" in the sense that it is unambiguously following traditional taxonomic practice of genus abbreviation. It is "implied" in the sense that nowhere did the authors actually state that "D." is intended as an abbreviation for the genus name "Ditrichum".

But the point is, even though "Ditrichum cornubicum" represents a different character string from "D. cornubicum", they would not constitute different "NameStrings", and hence would not warrant different NameUsage GUIDs. There are, of course, similarly "explicitly implied" abbreviations for trinomials.

Another example would be if a documentation instance (e.g., a book) listed a species heading as "Aus (Xea) bus", where "Xea" is intended as a subgenus. If, in the body of the text underneath this heading, the name "Aus bus" or "A. bus" is used, it would be "explicitly implied" that these are intended as short-hand abbreviations for the "full" NameString, "Aus (Xea) bus". Thus, only one GUID for this documentation instance.

There are other examples as well, and all introduce *some* degree of ambiguity -- but as I said before, NONE of the solutions are completely free of ambiguity.

I don't actually see a great deal of disagreement here. We are debating between only two alternatives.

Really?? Which two? I assume you mean "one kind of GUID" for taxon objects, vs. "two kinds of GUIDs". But earlier Rod Page had proposed three different "levels", with GUIDs for all three. Others seemed to like to three-level approach, but some slightly re-defined what the three levels ought to be. I pointed out at least 8 different "units" of a name, not all of which could be unambiguously pidgeonholed into either a "TaxonName" object or a "TaxonConcept" object. You advocate two kinds (levels? types? domains?) of GUID for taxon objects (i.e., Name & Concept). Personally, I think the ultimate goal should be as you describe: separate GUID domains/kinds/types for TaxonNames vs. TaxonConcepts. But Rod Page and others contributing to this thread have convinced me that this might be reaching for too much at this stage of the game. Thus, I am comfortable with the idea of establishing one domain/kind/type of GUID within the taxonomy realm, that is the most flexible and unambiguous of them all, and which can serve as a "stepping-stone" and/or surrogate to a future informatics world where we have an unambiguous distinction between a "TaxonName" object and a "TaxonConcept" object. Importantly, establishing GUIDs for usage instances now does not carry the risk that they will be rendered useless in the future, because I think there will always be value in identifying unique NameUsage instances.

Perhaps what we should do is each put together a page on the wiki expounding either of the approaches. It will be easier for some one coming along later to get up to speed on the arguments and add to them. We then have both cases clearly stated and we can see which one a consensus builds around.

I agree with this, and took a hasty first stab at it with "Scenario 5" on the page you created:

http://wiki.gbif.org/guidwiki/wikka.php?wakka=SeparateNamesAndConcepts

If I can find time, I'd be happy to expand it on a dedicated page, using a real-world example (maybe a PDF excerpt of a representative documentation instance). I'd be happy to provide the PDF example, if you wish.

This way we can move on to other stuff without having to make a decision on this one right now.

I don't think anyone is being prevented from starting a new thread of discussion -- that can happen anytime independednt of this discussion.

I'll probably not get my page finished till later in the week as I have other commitments - but certainly by Friday.

O.K., if you pick a real-world PDF example that we can both model, I'll follow whatever template you create. Or, if you'd like me to provide a PDF real-world example, I can easily do that as well.

Aloha, Rich

Richard L. Pyle, PhD Database Coordinator for Natural Sciences and Associate Zoologist in Ichthyology Department of Natural Sciences, Bishop Museum 1525 Bernice St., Honolulu, HI 96817 Ph: (808)848-4115, Fax: (808)847-8252 email: deepreef@bishopmuseum.org http://hbs.bishopmuseum.org/staff/pylerichard.html