Dogs are pulling a sled across the snow.
dogs compete in the idditarod
Just because dogs are pulling a sled across the snow that does not mean they are competing in the iditarod.
exists e1 x1 x2 x3.(n_snow(x3) & across(e1,x3) & Theme(e1,x2) & Actor(e1,x1) & v_pull(e1) & n_sled(x2) & n_dog(x1))
exists e1 x1 x2.(n_idditarod(x2) & in(e1,x2) & Actor(e1,x1) & v_compete(e1) & n_dog(x1))