| int p=3; int n=3; int d=5; int k=2;
ring rp = p,(x(1..n)),dp;
int s = size(maxideal(d));
s;
→ 21
// create a dense homogeneous ideal m, all generators of degree d, with
// generic (random) coefficients:
ideal m = maxideal(d)*random(p,s,n-2);
m;
→ m[1]=x(1)^3*x(2)^2-x(1)*x(2)^4+x(1)^4*x(3)-x(1)^3*x(2)*x(3)+x(1)*x(2)^3*x\
(3)+x(2)^4*x(3)+x(2)^3*x(3)^2+x(1)*x(2)*x(3)^3+x(1)*x(3)^4-x(3)^5
// look for zeros on the torus by checking all points (with no component 0)
// of the affine n-space over the field with p elements :
ideal mt;
int i(1..n); // initialize integers i(1),...,i(n)
int l;
s=0;
for (i(1)=1;i(1)<p;i(1)=i(1)+1)
{
for (i(2)=1;i(2)<p;i(2)=i(2)+1)
{
for (i(3)=1;i(3)<p;i(3)=i(3)+1)
{
mt=m;
for (l=1;l<=n;l=l+1)
{
mt=subst(mt,x(l),i(l));
}
if (size(mt)==0)
{
"solution:",i(1..n);
s=s+1;
}
}
}
}
→ solution: 1 1 2
→ solution: 1 2 1
→ solution: 1 2 2
→ solution: 2 1 1
→ solution: 2 1 2
→ solution: 2 2 1
"//",s,"solutions over GF("+string(p)+")";
→ // 6 solutions over GF(3)
// Now go to the field with p^3 elements:
// As long as there is no map from Z/p to the field with p^3 elements
// implemented, use the following trick: convert the ideal to be mapped
// to the new ring to a string and then execute this string in the
// new ring
string ms="ideal m="+string(m)+";";
ms;
→ ideal m=x(1)^3*x(2)^2-x(1)*x(2)^4+x(1)^4*x(3)-x(1)^3*x(2)*x(3)+x(1)*x(2)^\
3*x(3)+x(2)^4*x(3)+x(2)^3*x(3)^2+x(1)*x(2)*x(3)^3+x(1)*x(3)^4-x(3)^5;
// define a ring rpk with p^k elements, call the primitive element z. Hence
// 'solution exponent: 0 1 5' means that (z^0,z^1,z^5) is a solution
ring rpk=(p^k,z),(x(1..n)),dp;
rpk;
→ // # ground field : 9
→ // primitive element : z
→ // minpoly : 1*z^2+1*z^1+2*z^0
→ // number of vars : 3
→ // block 1 : ordering dp
→ // : names x(1) x(2) x(3)
→ // block 2 : ordering C
execute(ms);
s=0;
ideal mt;
for (i(1)=0;i(1)<p^k-1;i(1)=i(1)+1)
{
for (i(2)=0;i(2)<p^k-1;i(2)=i(2)+1)
{
for (i(3)=0;i(3)<p^k-1;i(3)=i(3)+1)
{
mt=m;
for (l=1;l<=n;l=l+1)
{
mt=subst(mt,x(l),z^i(l));
}
if (size(mt)==0)
{
"solution exponent:",i(1..n);
s=s+1;
}
}
}
}
→ solution exponent: 0 0 2
→ solution exponent: 0 0 4
→ solution exponent: 0 0 6
→ solution exponent: 0 1 0
→ solution exponent: 0 3 0
→ solution exponent: 0 4 0
→ solution exponent: 0 4 4
→ solution exponent: 0 4 5
→ solution exponent: 0 4 7
→ solution exponent: 1 1 3
→ solution exponent: 1 1 5
→ solution exponent: 1 1 7
→ solution exponent: 1 2 1
→ solution exponent: 1 4 1
→ solution exponent: 1 5 0
→ solution exponent: 1 5 1
→ solution exponent: 1 5 5
→ solution exponent: 1 5 6
→ solution exponent: 2 2 0
→ solution exponent: 2 2 4
→ solution exponent: 2 2 6
→ solution exponent: 2 3 2
→ solution exponent: 2 5 2
→ solution exponent: 2 6 1
→ solution exponent: 2 6 2
→ solution exponent: 2 6 6
→ solution exponent: 2 6 7
→ solution exponent: 3 3 1
→ solution exponent: 3 3 5
→ solution exponent: 3 3 7
→ solution exponent: 3 4 3
→ solution exponent: 3 6 3
→ solution exponent: 3 7 0
→ solution exponent: 3 7 2
→ solution exponent: 3 7 3
→ solution exponent: 3 7 7
→ solution exponent: 4 0 0
→ solution exponent: 4 0 1
→ solution exponent: 4 0 3
→ solution exponent: 4 0 4
→ solution exponent: 4 4 0
→ solution exponent: 4 4 2
→ solution exponent: 4 4 6
→ solution exponent: 4 5 4
→ solution exponent: 4 7 4
→ solution exponent: 5 0 5
→ solution exponent: 5 1 1
→ solution exponent: 5 1 2
→ solution exponent: 5 1 4
→ solution exponent: 5 1 5
→ solution exponent: 5 5 1
→ solution exponent: 5 5 3
→ solution exponent: 5 5 7
→ solution exponent: 5 6 5
→ solution exponent: 6 1 6
→ solution exponent: 6 2 2
→ solution exponent: 6 2 3
→ solution exponent: 6 2 5
→ solution exponent: 6 2 6
→ solution exponent: 6 6 0
→ solution exponent: 6 6 2
→ solution exponent: 6 6 4
→ solution exponent: 6 7 6
→ solution exponent: 7 0 7
→ solution exponent: 7 2 7
→ solution exponent: 7 3 3
→ solution exponent: 7 3 4
→ solution exponent: 7 3 6
→ solution exponent: 7 3 7
→ solution exponent: 7 7 1
→ solution exponent: 7 7 3
→ solution exponent: 7 7 5
"//",s,"solutions over GF("+string(p^k)+")";
→ // 72 solutions over GF(9)
|