Attendees for a presentation or lecture sit in blue chairs.
An audience is at an event.
attendees are audience and presentation or lecture is an event
exists e1 s1 x1 x2 x3.(in(e1,x3) & n_chair(x3) & a_blue(s1) & Theme(s1,x3) & Actor(e1,x1) & v_sit(e1) & for(x1,x2) & (n_presentation(x2) | n_lecture(x2)) & n_attendee(x1))
exists p1 x1.(exists x2.(at(x1,x2) & n_event(x2)) & n_audience(x1))