[GAP Forum] quotients in polynomial rings

[Larry Wilson]

Perhaps this question has a very simple answer, but I have not been able
to figure it out and would love to have some guidance.  I would like to be
able to do something like work in Z_4[x]/(x^8-1).  I thought I was on the
right track with:

GAP4, Version: 4.4.2 of 18-Mar-2004, sparc-sun-solaris2.8-cc
gap> A := FreeAlgebraWithOne(Integers, 1);;
gap> x := GeneratorsOfAlgebra(A)[2];
(1)*x.1
gap> I := Ideal(A, [x^8-1*x^0, 4*x^0]);
<two-sided ideal in <free left module over Integers, and ring-with-one,
with 1 generators>, (2 generators)>
gap> hom := NaturalHomomorphismByIdeal(A, I);
Error, no method found! For debugging hints type ?Recovery from
NoMethodFound
Error, no 1st choice method found for
`GeneratorsOfLeftOperatorRingWithOne' on 1 arguments called from
GeneratorsOfAlgebraWithOne( image ) called from
<function>( <arguments> ) called from read-eval-loop

Any help would be much appreciated,

Larry