Violinists are paying music together.
A string quartet is performing in front of an audience.
violinists playing music together does not imply they are performing in front of audience.
exists e1 s1 x1 x2.(a_together(s1) & Manner(e1,s1) & Theme(e1,x2) & Actor(e1,x1) & v_pay(e1) & n_music(x2) & n_violinist(x1))
exists e1 x1 x2 x3 x4.(in(e1,x3) & of(x3,x4) & n_audience(x4) & n_front(x3) & Actor(e1,x1) & v_perform(e1) & n_quartet(x1) & of(x1,x2) & n_string(x2))