Several girls are having a discussion after rollerskating.
Several girls are having a discussion
Several girls are having a discussion in both sentences which implies they are the same girls.
exists e1 e2 s1 x1 x2.(after(e1,e2) & Actor(e2,x1) & v_rollerskate(e2) & Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & n_discussion(x2) & n_girl(x1) & a_several(s1) & Theme(s1,x1))
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & n_discussion(x2) & n_girl(x1) & a_several(s1) & Theme(s1,x1))