
theorem Th72:
  for C1,C2 being category holds C2|^C1,eval(C1,C2) is_exponent_of C1,C2
  proof
    let C1,C2 be category;
    set T = the categorical_exponent of C1,C2;
    consider C be category, E be Functor of C [x] C1,C2 such that
A1: T = [C,E] & E is covariant & C,E is_exponent_of C1,C2 by Def35;
    thus thesis by A1;
  end;
