Notation ring_rw_correct :=
(ring_rw_correct Rsth Reqe ARth CRmorph pow_th cdiv_th get_sign_spec).
Notation ring_rw_pow_correct :=
(ring_rw_pow_correct Rsth Reqe ARth CRmorph pow_th cdiv_th get_sign_spec).
Notation ring_correct :=
(ring_correct Rsth Reqe ARth CRmorph pow_th cdiv_th).
(* simplify a field expression into a fraction *)
Definition display_linear l num den :=
let lnum := NPphi_dev l num in
match den with
| Pc c => if ceqb c cI then lnum else lnum / NPphi_dev l den
| _ => lnum / NPphi_dev l den
end.
Definition display_pow_linear l num den :=
let lnum := NPphi_pow l num in
match den with
| Pc c => if ceqb c cI then lnum else lnum / NPphi_pow l den
| _ => lnum / NPphi_pow l den
end.

Theorem Field_correct n l lpe fe1 fe2 :
Ninterp_PElist l lpe ->
forall lmp, Nmk_monpol_list lpe = lmp ->
forall nfe1, Fnorm fe1 = nfe1 ->
forall nfe2, Fnorm fe2 = nfe2 ->
Peq ceqb (Nnorm n lmp (num nfe1 * denum nfe2))
(Nnorm n lmp (num nfe2 * denum nfe1)) = true ->
PCond l (condition nfe1 ++ condition nfe2) ->
FEeval l fe1 == FEeval l fe2.