A man is lying on an air mattress.
The man is walking.
One cannot lie on a air mattress and be walking at the same time
exists e1 x1 x2 x3.(on(e1,x2) & n_mattress(x2) & of(x2,x3) & n_air(x3) & Actor(e1,x1) & v_lie(e1) & n_man(x1))
exists e1 x1.(n_man(x1) & Actor(e1,x1) & v_walk(e1))