What is the difference between rdf:_1....rdf_n and rdf:_li?

Question

What is the difference between rdf:_1....rdf_n and rdf:_li?

Can I use these in all rdf container (Seq, Bag, Alt) or not?

Answer 1

The :_n properties are equivalent to :li elements used in order. Anywhere where you're using :_1, :_2, etc., in order, you can use :li. Not only can you use them with all the RDF containers, you can use them with other resources too.

Note: This makes it look like :li is a property, but it's not. It's a special element for the RDF/XML syntax that gets interpreted according to special rules; it's syntactic sugar. This is similar to how a is used in Turtle—a itself isn't a property, but the syntax says that where a is used like a property, the actual property is rdf:type.

From the RDF/XML Syntax Specification (emphasis added):

2.15 Container Membership Property Elements: rdf:li and rdf:_n

RDF has a set of container membership properties and corresponding property elements that are mostly used with instances of the rdf:Seq, rdf:Bag and rdf:Alt classes which may be written as typed node elements. The list properties are rdf:_1, rdf:_2 etc. and can be written as property elements or property attributes as shown in Example 17. There is an rdf:li special property element that is equivalent to rdf:_1, rdf:_2 in order, explained in detail in section 7.4. The mapping to the container membership properties is always done in the order that the rdf:li special property elements appear in XML — the document order is significant. The equivalent RDF/XML to Example 17 written in this form is shown in Example 18.

Also, from RDF Vocabulary Description Language 1.0: RDF Schema (emphasis added):

5.1.5 rdfs:ContainerMembershipProperty

The rdfs:ContainerMembershipProperty class has as instances the properties rdf:_1, rdf:_2, rdf:_3 ... that are used to state that a resource is a member of a container. rdfs:ContainerMembershipProperty is a subclass of rdf:Property. Each instance of rdfs:ContainerMembershipProperty is an rdfs:subPropertyOf the rdfs:member property.

Given a container C, a triple of the form:

C rdf:_nnn O

where nnn is the decimal representation of an integer greater than 0 with no leading zeros, states that O is a member of the container C.

Container membership properties may be applied to resources other than containers.