Therefore, each value is either a literal value or a non-literal value:

Therefore, each value is either a literal value or a non-literal value:

What it says is that I(ex:a) is a literal value, ie that the uriref 'ex:a' denotes a literal value.

What it says is that I(ex:a) is a literal, ie that the uriref 'ex:a' denotes a literal.

What it says is that I(ex:a) is a literal value, ie that the uriref 'ex:a' denotes a literal value.

A symbolic constant is a name given to a constant literal value.

It does not specify exactly which literal value it denotes.

It preserves the literal value of the next character that follows.

RDF provides for XML content as a possible literal value.

RDF provides for XML content as possible literal value.

RDF provides for XML content as a possible literal value.

RDF provides for XML content as a possible literal value.

RDF provides for XML content as possible literal value.

Such references must be contained entirely within the literal entity value.

Any of those properties might use the simple literal value, or a more complex structured value.