Procedure from library grobcov.lib (see grobcov_lib).
Usage:
pnormalf(f,E,N);
f: the polynomial in Q[a][x] (a=parameters, x=variables) to be
reduced modulo V(E) \ V(N) of a segment in Q[a].
E: the null conditions ideal in Q[a]
N: the non-null conditions in Q[a]
Return:
a reduced polynomial g of f, whose coefficients are reduced
modulo E and having no factor in N.
Note:
Should be called from ring Q[a][x].
Ideals E and N must be given by polynomials in Q[a].