A class full of students.
A classroom full of students.
a classroom is naturally where a class it
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.(a_topic(x1) & of(s1,x3) & n_student(x3) & Theme(s1,x2) & a_full(s1) & (x1 = x2) & n_classroom(x1))