End IdomainUnit.
Module Field.
Include IdomainDefs.
Export IdomainDefs.
Include CommonIdomain.
Section FieldDivision.
Variable F : fieldType.
Implicit Type p q r d : {poly F}.

Lemma cubic_irreducible p :
1 < size p <= 4 -> (forall x, ~~ root p x) -> irreducible_poly p.