ORA-DM-PROPERTIES-AMBIGUITY

*Data Model, Section 4.2.1 Overview*
Following the numbered list with 7 items, it says "the children of the 
document node must not be empty".
This sentence is ambiguous.
It could mean "The [children] property of the document information item 
may not be empty" or it may mean "Each child of the document node may 
not be empty (ie, each child must have children of its own)."
This shows two things:
1. It is good to have special notation, such as the square brackets, to 
mark properties, especially when the name of the property is plural.
2. It is good to write universal quantifiers in the singular ("each 
child") rather than the plural ("the children").

Also, we read "the children of the document node must not be empty and 
consist exclusively of element nodes, etc."
This is ambiguous: does it mean "must not be empty and must not 
consist..." or does it mean "must not be empty and must consist..."