premise: Many people are on a party.
hypothesis: People are celebrating someone's birthday.
explanation_1: A party is not always someone's birthday.  There are several types of parties that people can have.
premise_logic: exists p1 x1.(exists x2.(on(x1,x2) & n_party(x2)) & n_people(x1) & n_quantity(x1))
hypothesis_logic: exists e1 x1 x2 x3.(Theme(e1,x3) & Actor(e1,x1) & v_celebrate(e1) & n_birthday(x3) & of(x3,x2) & n_person(x2) & n_people(x1))
premise_sim: exists x1.(n_quantity(x1) & n_people(x1) & exists x2.(on(x1,x2) & n_party(x2)))
hypothesis_sim: exists e1 x1 x2 x3.(v_celebrate(e1) & of(x3,x2) & n_person(x2) & n_people(x1) & n_birthday(x3) & Theme(e1,x3) & Actor(e1,x1))