clear;
q:=RandomPrime(50);
Fq:=GF(q);
E:=EllipticCurve([Fq|Random(Fq),Random(Fq)]);

P:=Random(E); Q:=Random(E); R:=Random(E); S:=Random(E);

D1:=2*Divisor(P)-3*Divisor(Q);
D2:=3*Divisor(Q)+Divisor(R)-Divisor(S);

Degree(D1);
Degree(D2);
Degree(D1+D2);

Support(D1); 
Support(D2);
Support(D1+D2);

