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D.2.4.7 pnormalform
Procedure from library grobcov.lib (see grobcov_lib).
- Usage:
- pnormalform(f,N,W);
f: the polynomial to be reduced modulo (N,W) a reduced representation
of a segment in the parameters.
N: the null conditions ideal
W: the non-null conditions (set of irreducible polynomials)
- Return:
- a reduced polynomial g of f, whose coefficients are reduced
modulo N and having no factor in W.
- Note:
- Should be called from ring Q[a][x], and the global rings @R, @P
and @RP must be defined. These rings can be created by calling
previously setglobalrings();
Ideals N and W must be given by polynomials
in the parameters forming a reduced-representation (see
definition in the paper).
Example:
| LIB "grobcov.lib";
ring R=(0,a,b,c),(x,y),dp;
setglobalrings();
poly f=(b^2-1)*x^3*y+(c^2-1)*x*y^2+(c^2*b-b)*x+(a-bc)*y;
ideal N=(ab-c)*(a-b),(a-bc)*(a-b);
ideal W=a^2-b^2,bc;
def r=redspec(N,W);
pnormalform(f,r[1],r[2]);
==> xy2+(b)*x
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