# In XPath 2.0 We Have

*Sequences* of *Items*

- XPath 2.0 does not center on a single document tree, but on
arbitrary data sets
- These can be arranged in
**sequences** of **items**
- sequences are lists, ordered sets of
- pointers to nodes (which still have identity) and
- simple-typed
*values*

- may contain duplicates

`count($node-set) =
count($node-set | $node-set)` is still true

(due to semantics of “`|`”, the union operator)
- But now we can also say
`($node-set , $node-set)`
- A sequence of all the nodes in
`$node-set` (in document order), *then all the same nodes again*