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D.5.4.5 normalForm

Procedure from library divisors.lib (see divisors_lib).

Usage:
normalForm(A); A = divisor.

Assume:
A is a divisor on X.

Return:
different representative of the same divisor on X

Theory:
The procedure will cancel common components of numerator and denominator.

Example:
 
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 A = makeDivisor(ideal(x,z),ideal(1));
divisor B = makeDivisor(ideal(x,y),ideal(1));
divisor D = (A+B)+multdivisor(-1,B);
D;
==> (x,yz) - (y,x)
==> 
normalForm(D);
==> (z,x) - (1)
==>