2 guitarists playing on stage.
2 violinists are playing.
Guitarists are not the same as violinists.
exists e1 x1 x2 x3.(a_topic(x1) & on(e1,x3) & n_stage(x3) & Actor(e1,x2) & v_play(e1) & (x1 = x2) & n_guitarist(x1) & n_date(x1) & a_date_day_02(x1) & a_date_day_02(x1))
exists e1 x1.(Actor(e1,x1) & v_play(e1) & n_violinist(x1) & n_date(x1) & a_date_day_02(x1) & a_date_day_02(x1))