Men wearing hard hats and safety vests are working.
People wearing hats and vests are working.
Hats are not necessarily hard hats and vests are not particularly safety vests.
exists e2 e1 s1 x1 x2 x3 x4 x5.(Actor(e2,x1) & v_work(e2) & subset_of(x4,x1) & n_vest(x4) & of(x4,x5) & n_safety(x5) & subset_of(x2,x1) & n_hat(x2) & a_hard(s1) & Theme(s1,x2) & Actor(e1,x2) & v_wear(e1) & of(x2,x3) & n_man(x3))
exists e2 e1 x1 x2 x3 x4 x5.(Actor(e2,x1) & v_work(e2) & Theme(e1,x3) & Actor(e1,x2) & v_wear(e1) & subset_of(x5,x3) & n_vest(x5) & subset_of(x4,x3) & n_hat(x4) & (x1 = x2) & n_people(x1))