Module UnityRootTheory.
Notation "n .-unity_root" := (root_of_unity n) : unity_root_scope.
Notation "n .-primitive_root" := (primitive_root_of_unity n) : unity_root_scope.
Open Scope unity_root_scope.
Definition unity_rootE := unity_rootE.
Definition unity_rootP := @unity_rootP.
Arguments unity_rootP {R n z}.
Definition prim_order_exists := prim_order_exists.
Notation prim_order_gt0 :=  prim_order_gt0.
Notation prim_expr_order := prim_expr_order.
Definition prim_expr_mod := prim_expr_mod.
Definition prim_order_dvd := prim_order_dvd.
Definition eq_prim_root_expr := eq_prim_root_expr.
Definition rmorph_unity_root := rmorph_unity_root.
Definition fmorph_unity_root := fmorph_unity_root.
Definition fmorph_primitive_root := fmorph_primitive_root.
Definition max_unity_roots := max_unity_roots.
Definition mem_unity_roots := mem_unity_roots.
Definition prim_rootP := prim_rootP.
End UnityRootTheory.
Section DecField.
Variable F : decFieldType.

(* Specifications: *)
Lemma dec_factor_theorem (p : {poly F}) :
{s : seq F & {q : {poly F} | p = q * \prod_(x <- s) ('X - x%:P)
/\ (q != 0 -> forall x, ~~ root q x)}}.