== and != have the same semantics as Java's == operator (identity), not the
equals() method (equality)
>> and << compare single nodes and sequences of single nodes for document order
The precedes operator returns true
if the first operand node is reachable from the second operand node
using the
preceding axis; otherwise it returns false.
The follows operator returns true
if the first operand node is reachable from the second operand node
using the following axis; otherwise it returns false.