Singular

LIB "primdecint.lib";
ring R=integer,(a,b,c,d),dp;
ideal I1=9,a,b;
ideal I2=3,c;
ideal I3=11,2a,7b;
ideal I4=13a2,17b4;
ideal I5=9c5,6d5;
ideal I6=17,a15,b15,c15,d15;
ideal I=intersectZ(I1,I2);
I=intersectZ(I,I3);
I=intersectZ(I,I4);
I=intersectZ(I,I5);
I=intersectZ(I,I6);
minAssZ(I);
==> [1]:
==>    _[1]=d
==>    _[2]=c
==> [2]:
==>    _[1]=b
==>    _[2]=a
==> [3]:
==>    _[1]=2
==>    _[2]=c
==> [4]:
==>    _[1]=3
==> [5]:
==>    _[1]=13
==>    _[2]=b
==> [6]:
==>    _[1]=17
==>    _[2]=a
ideal J=intersectZ(ideal(17,a),ideal(17,a2,b));
minAssZ(J);
==> [1]:
==>    _[1]=17
==>    _[2]=a
ideal K=intersectZ(ideal(9,a+3),ideal(9,b+3));
minAssZ(K);
==> [1]:
==>    _[1]=3
==>    _[2]=b
==> [2]:
==>    _[1]=3
==>    _[2]=a