A man and a pelican on a boardwalk.
Two pelicans on a boardwalk.
A man and a pelican are not two pelicans.
exists s1 x1 x2 x3.(a_topic(s1) & subset_of(x2,s1) & on(x2,x3) & n_boardwalk(x3) & n_pelican(x2) & subset_of(x1,s1) & n_man(x1))
exists x1 x2.(a_topic(x1) & on(x1,x2) & n_boardwalk(x2) & n_pelican(x1) & card_eq_2(x1))