Three people, are having a casual conversation.
The conversation is not formal.
If a conversation is casual, it is not formal.
exists e1 s1 x1 x2.(Theme(e1,x2) & Actor(e1,x1) & v_have(e1) & n_conversation(x2) & a_casual(s1) & Theme(s1,x2) & n_people(x1) & card_eq_3(x1))
exists x1.(n_conversation(x1) & -exists s1.(Theme(s1,x1) & a_formal(s1)))