-  delete(+List1, @Elem, -List2) is det
 - Delete matching elements from a list. True when List2 is a list
with all elements from List1 except for those that unify with
Elem. Matching Elem with elements of List1 is uses 
\+ Elem \=
H, which implies that Elem is not changed.
- See also
 - - select/3, subtract/3.
 
- deprecated
 - - There are too many ways in which one might want to
delete elements from a list to justify the name.
Think of matching (= vs. ==), delete first/all,
be deterministic or not.