set(expand_relational_defs).

formulas(assumptions).
  all x all y (subset(x,y) <-> (all z (member(z,x) -> member(z,y)))).
end_of_list.

formulas(goals).
  all x all y all z (subset(x,y) & subset(y,z) -> subset(x,z)).
end_of_list.
