A competition on horses on a beautiful day amongst green.
The very first horse competition in WA state is being held.
You can not infer it's the first competition.
exists s1 s2 x1 x2 x3 x4.(a_topic(x1) & on(x1,x2) & on(x2,x3) & n_green(x3) & a_amongst(s2) & Theme(s2,x3) & of(x3,x4) & n_day(x4) & a_beautiful(s1) & Theme(s1,x3) & n_horse(x2) & n_competition(x1))
exists e1 s1 x1 x2 x3 x4.(n_competition(x1) & of(x1,x2) & n_horse(x2) & a_first(s1) & Theme(s1,x1) & r_very(x1) & Theme(e1,x1) & v_hold(e1) & in(x1,x3) & n_state(x3) & (x3 = x4) & ne_org_wa(x4))