
formulas(assumptions).

% Prover9 should produce a proof immediately.

all x all y (subset(x,y) <->
             (all z (member(z,x) -> 
                     member(z,y)))) # label(definition_subset).

end_of_list.

formulas(goals).

all x all y all z (subset(x,y) & subset(y,z) ->
                   subset(x,z)) # label(subset_is_transitive).

end_of_list.


