60.2-1 Factors
‣ Factors( F )( method )

Factoring of polynomials over abelian number fields consisting of cyclotomics works in principle but is not very efficient if the degree of the field extension is large.

gap> x:= Indeterminate( CF(5) );
x_1
gap> Factors( PolynomialRing( Rationals ), x^5-1 );
[ x_1-1, x_1^4+x_1^3+x_1^2+x_1+1 ]
gap> Factors( PolynomialRing( CF(5) ), x^5-1 );
[ x_1-1, x_1+(-E(5)), x_1+(-E(5)^2), x_1+(-E(5)^3), x_1+(-E(5)^4) ]