Subcmd 
Description 
create 
value...

Creation of a list representing a set, i.e. without
any duplicates. If the input contained such, they will
be removed.
The result is a list, but without any duplicates
in it.



contains 
set element

Checks wether the given <set> contains the specified
<element>.
Returns a boolean value, i.e. 0 or 1. The latter is
returned if the element is a member of the set.



union 
set...

Computes the union of the sets it was called with.
The result is a list representing a set consisting
of the union of the sets used as arguments to the
command. There are no duplicates in the result.



intersect 
set...

Computes the intersection of the sets it was called with.
The result is a list representing a set consisting
of the interseection of the sets used as arguments to the
command.



diff 
A B

Computes the set difference A  B of the two sets it
was called with.
The result is a list representing a set containing the
difference A  B.



symdiff 
A B

Computes the symmetrical set difference (AB)+(BA) of
the two sets it was called with. + denotes
union,  denotes set difference.
This is esssentially just the complementary operation to
the intersection of A and B.
The result is a list representing a set containing the
symmetrical set difference of A and B.



empty 
set

Checks wether the argument represents an empty set or not.
The result is a boolean value, 0 or 1. The latter is
returned if the argument represents an empty set.



size 
set

Returns the number of elements in the argument set.


