D.15.5.8 degreeDivisor

Usage:

degreeDivisor(A); A = divisor.

Assume:

A is a divisor on X.

Return:

The degree of A.

Theory:

We compute difference of the degrees of the numerator and denominator ideals.

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));
degreeDivisor(P);