JSON vs XML

Interesting article on Quoderat:

In the current JSON vs. XML debate (see Bray, Winer, Box, Obasanjo, and many others), there are three things that important to understand:

  1. There is no information that can be represented in an XML document that cannot be represented in a JSON document.
  2. There is no information that can be represented in a JSON document that cannot be represented in an XML document.
  3. There is no information that can be represented in an XML or JSON document that cannot be represented by a LISP S-expression.

They are all capable of modeling recursive, hierarchical data structures with labeled nodes. Do we have a term for that, like Turing completeness for programming languages? It would certainly be convenient in discussions like this.