[GAP Forum] trace of an algebraic element

[xiaolei zhang]

hello.

I try to calculate the trace of an element, like this:

GAP4, Version: 4.4.12 of 17-Dec-2008, x86_64-unknown-linux-gnu-gcc
gap> F2:=GF(2);
GF(2)
gap> x:=X(GF(2), "x");
x
gap> F:=AlgebraicExtension(F2, x^2+x+1);
<field of size 4>
gap> r:=RootOfDefiningPolynomial(F);
a
gap> Trace(r);
Error, no method found! For debugging hints type ?Recovery from NoMethodFound
Error, no 1st choice method found for `AsDivisionRing' on 2 arguments
called ......

I had tried Trace(F4, F2, r) and  Trace(F4, r), they didn't work.

Thanks.