
theorem
  for F being Field holds for a,b being Element of F
  holds osf(F).(a,b) = (comp F).(osf(F).(b,a))
proof
  let F be Field;
  let a,b be Element of F;
  osf(F).(a,b) = (the addF of F).(a,(comp F).b) by Def1
    .= a+-b by VECTSP_1:def 13
    .= -(b-a) by RLVECT_1:33
    .= (comp F).(b+-a) by VECTSP_1:def 13
    .= (comp F).((the addF of F).(b,(comp F).a)) by VECTSP_1:def 13;
  hence thesis by Def1;
end;
