A group of people are attending a conference.
The speaker has been assassinated.
The speaker is one person, not a group.
exists e1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_attend(e1) & n_conference(x3) & of(x1,x2) & n_people(x2) & n_group(x1))
exists e1 x1.(n_speaker(x1) & Theme(e1,x1) & v_assassinate(e1))