Eleven girls in white tutus stand and pose on stage.
Eleven ballerinas pose on stage.
Girls in white tutus are not necessarily ballerinas. They could be actors wearing costumes.
exists e1 e2 s1 s2 x1 x2 x3 x4 x5 x6 x7.(on(e2,x7) & n_stage(x7) & Actor(e2,x4) & v_pose(e2) & in(x4,x6) & n_tutu(x6) & a_white(s2) & Theme(s2,x6) & n_girl(x4) & (x4 = x5) & ne_org_eleven(x5) & Actor(e1,x1) & v_stand(e1) & in(x1,x3) & n_tutu(x3) & a_white(s1) & Theme(s1,x3) & n_girl(x1) & (x1 = x2) & ne_org_eleven(x2))
exists e1 x1 x2 x3.(on(e1,x3) & n_stage(x3) & Actor(e1,x1) & v_pose(e1) & n_ballerina(x1) & (x1 = x2) & ne_nam_eleven(x2))