Several dogs are walking around on a brick street.
A single dog is running on a brick street
Several implies more than a single of something.
exists e1 p1 s1 x1 x2 x3.(on(e1,x2) & n_street(x2) & of(x2,x3) & n_brick(x3) & exists s2.(Theme(s2,x1) & a_around(s2)) & Topic(e1,p1) & Actor(e1,x1) & v_walk(e1) & n_dog(x1) & a_several(s1) & Theme(s1,x1))
exists e1 s1 x1 x2 x3.(on(e1,x2) & n_street(x2) & of(x2,x3) & n_brick(x3) & Actor(e1,x1) & v_run(e1) & n_dog(x1) & a_single(s1) & Theme(s1,x1))