Singular

D.5.4.1 makeDivisor

Usage:

makeDivisor(I ,J); I = ideal, J = ideal.

Assume:

I and J are ideals in a qring Q of a smooth irreducible variety X such that any ideal in Q satisfies the S2 condition.

Return:

a divisor on X

Theory:

The procedure will eliminate all components which are not of codimension 1. The S2 condition requires that every proper nonzero principal ideal has pure codimension 1.

LIB "divisors.lib";
ring r=31991,(x,y,z),dp;
ideal I = y^2*z - x*(x-z)*(x+3*z);
qring Q = std(I);
divisor P = makeDivisor(ideal(x,z),ideal(1));