Functions on Sets.

In each of following, EXPR must evaluate to a set.

  1. arb(EXPR)

    . An element of

    EXPR

    , selected arbitrarily. If the value of

    EXPR

    is

    {}

    , then the value of the function is

    OM

    .

  2. pow(EXPR)

    . The value is the set of all subsets of the value of

    EXPR

    .

  3. npow(EXPR, EXPR)

    . One

    EXPR

    must be a set, and the other a non-negative integer. The value is the set of all subsets of the set whose cardinality is equal to the integer. This func is defined in

    .isetlrc

    . This will eventually change. If you do not have the standard

    .isetlrc

    , you do not have this func.