A baby sits in a smiling woman's lap.
A father and son are skiing.
The subject cannot be a baby and a father simultaneously.
exists e2 e1 x1 x2 x3.(in(e1,x3) & n_lap(x3) & of(x3,x2) & n_woman(x2) & Actor(e2,x2) & v_smile(e2) & Actor(e1,x1) & v_sit(e1) & n_baby(x1))
exists p1 x1 x2 x3.(exists x4.((x1 = x4) & n_skiing(x4)) & n_son(x3) & n_father(x2) & subset_of(x3,x1) & subset_of(x2,x1))