skos:prefLabel without language tag

Dear all

[Please ignore the previous partial message sent by mistake. Apologies for
the noise]

The SKOS specification about language tags has only the restriction.
"A resource has no more than one value of skos:prefLabel per language tag"
It does says otherwise that the language tag is optional for labels, but all
examples given in the specification have language tags.

So it's unclear if the following are conformant for a given skos:Concept:

#1 Having exactly one skos:preflabel without language tag.
#2 Having more than one skos:prefLabel without language tag.

Independently of the semantics underlying such declarations.
#1 could be used for concepts having the same lexical form in any language
(at least in any language used in the concept scheme), or because they are
labels never translated (pizza, football, ...)
#2 does not make sense in my opinion, but it's unclear it's formally
forbidden

Bernard

-- 
Bernard Vatant
Senior Consultant
Vocabulary & Data Integration
Tel:       +33 (0) 971 488 459
Mail:     bernard.vatant@mondeca.com
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