Guidelines for capitalization on RDF Labels?

         <rdfs:label>Athlete</rdfs:label>  vs. <rdfs:label>athlete</rdfs:label>

Are there no guidelines for capitalization on RDF labels? I've experimented with connecting a Natural Language Engine to some existing ontologies but the lack of consistent capitalization on label elements is problematic.

Could/should ontology authors follow language rules for capitalization in their labels (and stop blindly capitalizing every label or sometimes every word in every label)?

Should this be in the RDF spec?

Could/should ontology authors follow language rules for capitalization in their labels (and stop blindly capitalizing every label or sometimes every word in every label)?

Well, generally speaking, yes, but it depends on the purpose these authors have written their ontology for. They may well have Capitalized Everything Because Their Application Uses Labels as Headlines, for example. Which is perfectly legit.

Should this be in the RDF spec?

Definitely not. The RDF spec defines a standard data modeling language. The whole point of it is that it doesn't restrict you in what you can model in it. It is perfectly acceptable that sometimes the value of an rdfs:label property is not "properly" capitalized (what if you are modeling an ontology on commmon spelling mistakes, for example?)

As for your specific problem: surely if it is just the capitalization, then matching shouldn't be a real problem? Just convert everything to lowercase and then do a match.