A class full of students.
A class full of students in a classroom.
a classroom is where a class would be
exists s1 x1 x2 x3.(a_topic(x1) & of(s1,x3) & n_student(x3) & Theme(s1,x2) & a_full(s1) & (x1 = x2) & n_class(x1))
exists s1 x1 x2 x3 x4.(a_topic(x1) & of(s1,x3) & in(x3,x4) & n_classroom(x4) & n_student(x3) & Theme(s1,x2) & a_full(s1) & (x1 = x2) & n_class(x1))