
theorem Th27:
  for F being Field holds for a being Element of F holds ovf(F).(a,1.F) = a
proof
  let F be Field;
  let a be Element of F;
  1.F is Element of NonZero F by STRUCT_0:2;
  hence ovf(F).(a,1.F) = omf(F).(a,revf(F).1.F) by Def2
    .= a*1.F by Th1
    .= a by REALSET2:21;
end;
