Operators 
                                <=  (Subset Of) 

     FUNCTION:  Tests for a Subset of

 OPERAND TYPE:  Compatible set types

  RESULT TYPE:  Boolean

      REMARKS:  When the operands =, <>, <, >, >=, or <= are of
                simple types, they must be compatible types; however, if
                one operand is of a real type, the other can be of an
                integer type.

                Strings are compared according to their extended ASCII
                charactor set.  Charactor type values are treated as
                string types.

                Packed strings can be compared if they have the same
                number of components.

                Pointers are equal only if they point to the same object.
                Only equal, <, >, are valid pointer comparison operators.

                Sets are compared according to its members.  a = b is True
                only  if a and b contain exactly the same members; otherwise,
                a <> b.  a <= b is True only if every member of a is also a
                member of b.  a >= b is True only if every member of b is
                also a member of a.

                When using the IN operator, it will return true when the
                value of the ordinal type operand is a member of the set
                type operand.