With the dam in the distance, the boy piggy backed onto the man in the black jacket holding a frisbee.
The boy is the man's son.
Just because the boy is with the man does not mean that he is the man's son.
exists e1 e2 s1 x1 x2 x3 x4 x5 x6 x7.(n_distance(x6) & n_dam(x5) & n_jacket(x4) & a_black(s1) & Theme(s1,x4) & n_man(x3) & n_piggy(x1) & of(x1,x2) & n_boy(x2) & for(e1,e2) & Theme(e2,x7) & Actor(e2,x1) & v_hold(e2) & n_frisbee(x7) & with(e1,x5) & in(x5,x6) & onto(e1,x3) & in(x3,x4) & Actor(e1,x1) & v_back(e1))
exists p1 x1 x2 x3.(n_son(x3) & of(x3,x2) & n_man(x2) & n_boy(x1) & (x1 = x3))