People at a kickboxing class.
The zombies are acrobats.
People are not zombies. Kickboxing and acrobats are different.
exists e1 x1 x2.(a_topic(x1) & at(x1,x2) & n_class(x2) & Actor(e1,x2) & v_kickbox(e1) & n_people(x1))
exists p1 x1.(n_zombie(x1) & exists x2.((x1 = x2) & n_acrobat(x2)))