Someone is preparing some kind of food.
Someone is cooking food
Preparing food is cooking food.
exists e1 x1 x2 x3.(Theme(e1,x2) & Actor(e1,x1) & v_prepare(e1) & of(x2,x3) & n_food(x3) & n_kind(x2) & n_person(x1))
exists p1 x1.(exists s1 x2.((x1 = x2) & n_food(x2) & a_cooking(s1) & Theme(s1,x2)) & n_person(x1))