
theorem
  for F being Field holds for a being Element of F holds
  osf(F).(0.F,a) = (comp F).a
proof
  let F be Field;
  let a be Element of F;
  thus osf(F).(0.F,a) = 0.F+(comp F).a by Def1
    .= (comp F).a by REALSET2:2;
end;
