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<div>On 19 Mar 2026, at 09:04, Markus Demleitner via semantics <semantics@ivoa.net> wrote:</div>
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<div>Dear Gregory,<br>
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<blockquote type="cite">Superficially it doesn't seem wrong to want to document "I'm using<br>
terms from version X of vocabulary Y", but, well, I've only thought<br>
about it superficially.<br>
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If it's an IVOA vocabulary, it's simple and clear: Just use its URI<br>
(something like http://www.ivoa.net/rdf/examples). These things are<br>
explicitly not versioned, and I'll passionately defend this design<br>
decision if you'd like me to.<br>
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UCDs, at this point, aren't a proper IVOA vocabulary, and will never<br>
exactly be, because they have a grammar that's (I think) impossible<br>
to map into RDF. So, for them I'd suggest "This is a ucd" would<br>
always mean referencing ivo://ivoa.net/standards/ucd.<br>
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<div>Of course vocabularies shouldn't have grammars, but there's no reason something grammared couldn't be represented by a vocabulary as long as vocabularies are simply collections of tokens used in some context to represent something useful, as UCD's obviously
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<div>Here's an example (yes, really ancient) :</div>
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<div><span class="Apple-tab-span" style="white-space:pre"></span><a href="https://www.astro.physik.uni-goettingen.de/~hessman/rdf/UCD1/index.html">https://www.astro.physik.uni-goettingen.de/~hessman/rdf/UCD1/index.html</a></div>
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<div>Rick</div>
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<div>Frederic Hessman</div>
<div>fhessma@uni-goettingen.de</div>
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