A man and his son in a grocery store.
A parent and child shopping for toys.
A man and his son are not the same as a parent and child.
exists s1 x1 x2 x3 x4.(a_topic(s1) & subset_of(x2,s1) & in(x2,x3) & n_store(x3) & of(x3,x4) & n_grocery(x4) & n_son(x2) & of(x2,x1) & n_male(x1) & subset_of(x1,s1) & n_man(x1))
exists s1 x1 x2 x3 x4.(a_topic(s1) & subset_of(x2,s1) & for(x2,x4) & n_toy(x4) & n_shopping(x2) & of(x2,x3) & n_child(x3) & subset_of(x1,s1) & n_parent(x1))