A man helping a boy ride a bicycle.
A woman is helping her son.
A man is not a woman, and helping one's son is not the same as helping a boy ride a bicycle.
exists x1 x2.(a_topic(x1) & all x3.(n_bicycle(x3) -> exists e1 x4 x5.(Theme(e1,x4) & Actor(e1,x2) & v_help(e1) & for(x4,x3) & n_ride(x4) & of(x4,x5) & n_boy(x5))) & (x1 = x2) & n_man(x1))
exists e1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_help(e1) & n_son(x2) & of(x2,x1) & n_female(x1) & n_woman(x1))