A small black and white dog on a leash wearing a shirt carrying a large stick.
Two dogs are going on a walk.
Not all dogs on leashes are going on a walk.  One dog does not imply the existence of two dogs.
exists e1 e2 s1 s2 s3 s4 x1 x2 x3 x4 x5 x6.(a_topic(x1) & on(x1,x2) & Theme(e2,x4) & Actor(e2,x3) & v_wear(e2) & Theme(e1,x6) & Actor(e1,x5) & v_carry(e1) & n_stick(x6) & a_large(s4) & Theme(s4,x6) & (x4 = x5) & n_shirt(x4) & (x2 = x3) & n_leash(x2) & n_dog(x1) & a_white(s3) & Theme(s3,x1) & a_black(s2) & Theme(s2,x1) & a_small(s1) & Theme(s1,x1))
exists e1 x1 x2.(on(e1,x2) & n_walk(x2) & Actor(e1,x1) & v_go(e1) & n_dog(x1) & card_eq_2(x1))