People in a dance
The group is fishing.
If a group is fishing it cannot be at a dance at the same time.
exists x1 x2.(a_topic(x1) & in(x1,x2) & n_dance(x2) & n_people(x1))
exists p1 x1.(n_group(x1) & exists x2.((x1 = x2) & n_fishing(x2)))