reserve o,m for set;
reserve C for Cartesian_category;
reserve a,b,c,d,e,s for Object of C;

theorem
  dom(term a) = a & cod(term a) = [1]C
proof
  [1]C is terminal & term a = term(a,[1]C) by Def8,Th14;
  hence thesis by CAT_3:35;
end;
