A very joyous fireman or emergency medical worker.
Nobody is happy.
If there is a joyous fireman, then it is not true that nobody is happy.
exists s1 s2.(a_topic(s1) & (n_fireman(s1) | exists s3 x1.(n_worker(s1) & a_medical(s3) & Theme(s3,s1) & of(s1,x1) & n_emergency(x1))) & a_joyous(s2) & Theme(s2,s1) & r_very(s1))
-exists s1 x1.(Theme(s1,x1) & a_happy(s1) & n_person(x1))