1#d note1 A set may either be an Array_Type or a List_Type object.\__newline__\
2  For a homogeneous collection of objects, it is better to\__newline__\
3  use an Array_Type. i.e., \exmp{[1,2,3]} instead of \exmp{\{1,2,3\}}.
4
5
6\function{complement}
7\synopsis{Extract the elements of a set that are not contained in other sets.}
8\usage{indices = complement (a, b, ..., c)}
9\description
10  This function computes the elements of the first argument (\exmp{a})
11  that are not contained in the sets given by the other arguments
12  (\exmp{b,...,c}) and returns them in the form of indices into the
13  first argument.
14\example
15#v+
16   a = {"foo", PI, 7};
17   b = [1,2,3,PI];
18   indices = complement (a, b);
19#v-
20  Upon return, \exmp{indices} will have the value \exmp{[0, 2]} since
21  \exmp{a[0]} and \exmp{a[2]} are not contained in \exmp{b}.
22\notes
23  \note1
24\seealso{intersection, ismember, union, unique}
25\done
26
27\function{intersection}
28\synopsis{Extract the common elements of two or more sets}
29\usage{indices = complement (a, b, ..., c)}
30\description
31  This function computes the common elements of two or more sets and
32  returns them in the form of indices into the first argument.
33\example
34#v+
35   a = {"foo", 7, PI};
36   b = {PI, "bar", "foo"};
37   indices = intersection (a, b);
38#v-
39  Upon return, \exmp{indices} will have the value \exmp{[0, 2]} since
40  \exmp{a[0]} and \exmp{a[2]} are the common elements of the sets.
41\notes
42  \note1
43\seealso{complement, ismember, union, unique}
44\done
45
46\function{ismember}
47\synopsis{test to see if the elements of one set are members of another}
48\usage{val = ismember (a, b)}
49\description
50  This function may be used to see which of the elements of the set
51  \exmp{a} are members of the set \exmp{b}.  It returns a boolean
52  array indicating whether or not the corresponding element of
53  \exmp{a} is a member of \exmp{b}.
54\notes
55  \note1
56\seealso{complement, intersection, union, unique}
57\done
58
59\function{union}
60\synopsis{Form a set of the unique elements of one ore more subsets}
61\usage{abc = union (a, b,..., c)}
62\description
63  This function interprets each of its arguments as a set, then merges
64  them together and returns only the unique elements.  The returned
65  value may either be an \dtype{Array_Type} or a \dtype{List_Type}
66  object.
67\notes
68  \note1
69\seealso{complement, intersection, ismember, unique}
70\done
71
72\function{unique}
73\synopsis{Get the indices of the unique elements of a set}
74\usage{indices = unique (A)}
75\description
76  This function returns an array of the indices of the unique elements
77  of a set.
78\notes
79  \note1
80\seealso{complement, intersection, ismember, union}
81\done
82