The woman walking the dog is holding the hand of the child on the unicycle.
A female is holding her son's hand while he rides a unicycle.
Just because she is holding the child's hand does not mean it is her son's.
exists e2 e1 x1 x2 x3 x4 x5 x6.(n_unicycle(x6) & n_child(x5) & n_hand(x4) & n_dog(x3) & n_woman(x1) & on(e2,x6) & Theme(e2,x4) & Actor(e2,x1) & v_hold(e2) & of(x4,x5) & Theme(e1,x3) & Actor(e1,x2) & v_walk(e1) & (x1 = x2))
exists e1 p1 x1 x2 x3.(exists e2 x4.(Theme(e2,x4) & Actor(e2,x2) & v_ride(e2) & n_unicycle(x4)) & n_male(x2) & while(e1,p1) & Theme(e1,x3) & Actor(e1,x1) & v_hold(e1) & n_hand(x3) & of(x3,x2) & n_son(x2) & of(x2,x1) & n_female(x1) & n_female(x1))