Singular

7.7.5.0. isFsat

Usage:

isFsat(I, F); I an ideal, F a poly

Return:

int, 1 if I is F-saturated and 0 otherwise

Purpose:

checks whether the ideal I is F-saturated

Note:

We check indeed that Ker(D--> F--> D/I) is 0, where D is the basering.

LIB "dmodapp.lib";
ring r = 0,(x,y),dp;
poly G = x*(x-y)*y;
def A = annfs(G);
setring A;
poly F = x3-y2;
isFsat(LD,F);
==> 1
ideal J = LD*F;
isFsat(J,F);
==> 0