D.4.9.2 normalI

Procedure from library reesclos.lib (see reesclos_lib).

Usage:

normalI(I [,p[,c]]); I an ideal, p and c optional integers

Return:

the integral closure of I,...,I^p. If p is not given, or p==0, compute the closure of all powers up to the maximum degree in t occurring in the generators of the closure of R[It] (so this is the last one that is not just the sum/product of the above ones). c is transferred to the procedure primeClosure and toggles its behavior in computing the integral closure of R[It].
The result is a list containing the closure of the desired powers of I as ideals of the basering.

Example:

LIB "reesclos.lib";
ring R=0,(x,y),dp;
ideal I = x2,xy4,y5;
list J = normalI(I);
I;
→ I[1]=x2
→ I[2]=xy4
→ I[3]=y5
J;                             // J[1] is the integral closure of I
→ [1]:
→    _[1]=x2
→    _[2]=y5
→    _[3]=-xy3