Lists, sets, and multisets

Hi it's me again,

I am confused about the use of the term "set" to describe @set objects. In the section Lists and Sets it is said that

A set represents an unordered set of values

Section 4.3.2 it is said that

While @list is used to describe ordered lists, the @set keyword is used to describe unordered sets.

So I thought to be correct assuming that I could optimize @set objects by removing duplicate values (using a set data structure internally), since it is described as an unordered set, a opposed to @list objects defined as an ordered list.

Now trying to pass the expansion tests, I cannot pass test 27 as it is indicated that "Duplicate values in @list and @set are not merged" which is not mentioned in the specification sections associated to @list and @set, and also means that a @set object is, in fact, not a set, but a multiset.

Note that I understand that @set is just syntactic sugar, associating multiple values to a subject property. Forcing an implementation to keep duplicate values in @set objects implies that duplicate RDF triples would have some kind of meaning, which they have not since a RDF graph is a set of triples, not a multiset.

Am I correct in my conclusion or is there something wrong with the expansion test 27? Or did I miss the explanation in the spec? Or is it just to avoid further complications (like, what should we do if there is a duplicate occurrence of the same node object, with the same id but not the same properties, etc.)

Start by comparing the JSON-LD 1.1 sections on Lists and Sets and section 4.3.2 on sets with expansion test 27 at tests/expand/0027-in.jsonld. Review the linked specification wording and test expectation together. Done means the duplicate-value behavior is unambiguous and any needed specification or test clarification is agreed upon.