A group of three people are talking.
A group of four people are talking.
Three is one less than four.
exists e1 x1 x2.(Actor(e1,x1) & v_talk(e1) & of(x1,x2) & n_people(x2) & card_eq_3(x2) & n_group(x1))
exists e1 x1 x2.(Actor(e1,x1) & v_talk(e1) & of(x1,x2) & n_people(x2) & card_eq_4(x2) & n_group(x1))