This is a MAGMA-readable 3-tuple. The first entry is a polynomial
f(x) of degree n which defines the degree n field
Kf generated by the eigenvalues
ap. The second entry is a sequence of sequences of
length n each of which defines ap on a basis
for Kf. The third entry defines an embedding of
that basis for Kf into the field
Q[x]/(f(x)).