set_y << Get Keys,
set_z << Get Keys,
set_w << Get Keys
set_z << Insert( set_w );
set_y << Remove( set_z );
To find the intersection of two sets, use the aa << Intersect message.
set_w << Intersect( set_z );
Given a list of names, which of them are not contained in Big Class.jmp? You can find the answer by taking the difference of the two sets of names.
names = Associative Array( names list );