A pianist and a singer are ready to perform.
They are on stage.
Ready to perform does not imply being on a stage.
exists p1 s1 x1 x2 x3.(Topic(s1,p1) & Actor(s1,x1) & a_ready(s1) & exists e1.(Actor(e1,x1) & v_perform(e1)) & subset_of(x3,x1) & n_singer(x3) & subset_of(x2,x1) & n_pianist(x2))
exists p1 x1.(n_thing(x1) & exists x2.(on(x1,x2) & n_stage(x2)))