Error using rdf:langString in union class expression

Question

Error using rdf:langString in union class expression

rjyounes opened this issue 3 years ago · comments

I tracked down the Protege error to this code:

bdo:LangStringOrNoColophon
	a rdfs:Datatype ;
	owl:equivalentClass [
		a rdfs:Datatype ;
		owl:unionOf (
			bdo:NoColophon
			rdf:langString
		) ;
	] ;
	.

The following also generates an error:

bdo:LangStringOrNoColophon
	a rdfs:Datatype ;
	owl:equivalentClass [
		a rdfs:Datatype ;
		owl:unionOf (
			rdf:langString
		) ;
	] ;
	.

As does

bdo:LangStringOrNoColophon
	a rdfs:Datatype ;
	owl:equivalentClass [
		a rdfs:Datatype ;
		owl:unionOf (
			xsd:integer
			rdf:langString
		) ;
	] ;
	.

The following does not generate an error is

bdo:LangStringOrNoColophon
	a rdfs:Datatype ;
	owl:equivalentClass rdf:langString ;
	.

owl:intersectionOf produces the same results. That is, an error is generated if and only if rdf:langString is used in a list.

Rebecca Younes commented 3 years ago

Fixed.

Elie Roux commented 3 years ago

thanks!

Elie Roux · Answer 1 · Mon Apr 12 2021 23:54:59 GMT+0800 (China Standard Time)

ah, thanks a lot for that!! We can remove this, but I think the original intent was to say that the range of bdo:colophon was either a xsd:integer or rdf:langString... out of curiosity, is there a was to express that?

Rebecca Younes · Answer 2 · Mon Apr 12 2021 23:57:16 GMT+0800 (China Standard Time)

Unfortunately, I have no idea what's wrong with it. I've sent a message to my Semantic Arts colleagues asking if anyone can explain it. I forgot to mention that the error is generated in Protege but not rdf-toolkit, so it could be a Protege problem.

Elie Roux · Answer 3 · Mon Apr 12 2021 23:59:01 GMT+0800 (China Standard Time)

oh wait, I think Protege is only using RDF 1.0 in which rdf:langString is rdf:PlainLiteral, because it uses an owl java library that doesn't handle RDF 1.1... I think it was a major reason why we didn't want to use it

Rebecca Younes · Answer 4 · Tue Apr 13 2021 00:56:55 GMT+0800 (China Standard Time)

It appears that RDF 1.0 didn't define rdf:langString at all: https://www.w3.org/TR/rdf11-new/.

However, yes, it could be some Protege oddity. We should probably ignore it.

Rebecca Younes · Answer 5 · Tue Apr 20 2021 22:43:05 GMT+0800 (China Standard Time)

Actually, Protege 5.5, which I'm using, does use RDF 1.1, so it's still not clear what causes this error.

Elie Roux · Answer 6 · Tue Apr 20 2021 22:46:21 GMT+0800 (China Standard Time)

ah, I'm glad they finally updated that! Well, as I said, you can remove this piece of code, we won't use it anymore as we're transitionning to shacl

Rebecca Younes · Answer 7 · Wed Apr 21 2021 21:14:30 GMT+0800 (China Standard Time)

Oh, I see what you're asking above about the range of bdo:colophon. Yes, there is a way to express a union domain in OWL. I will make that change and remove the LangStringOrNoColophon datatype.