I think Sage calls Maxima and Maxima is getting i (your variable)
and I (sqrt(-1)) mixed up. I guess this is a bug, but it might be
known already.
Anyway, using x's and y's might be safer:
sage: x,y = var('x,y')
sage: ineqs = [2*x+9*y>= - 0, -5*x-7*y>=-5, 3*x-2*y>= -6]
sage: solve_ineq(ineqs,[x,y])
[[x == (-32/31), y == (45/31)], [x == (-54/31), y == (12/31)], [x ==
2/3*y - 2, (12/31) < y, y < (45/31)], [x == (45/31), y == (-10/31)],
[x == -7/5*y + 1, (-10/31) < y, y < (45/31)], [x == -9/2*y, (-10/31) <
y, y < (12/31)], [max(2/3*y - 2, -9/2*y) < x, x < -7/5*y + 1, (-10/31)
< y, y < (45/31)]]
On Mon, May 3, 2010 at 5:04 AM, Diego Ruano <dru...@gmail.com> wrote:
> Hi,
>
> I would like to compute the solution of systems of inequalities over
> the integers. I have used the command "solve", but the solution is
> over the complex numbers.
>
> Something like:
>
> i, j = var('i,j')
> sol=solve([2*i+9*j>= - 0, -5*i-7*j>=-5, 3*i-2*j>= -6], i,j)
> sol
> [[i == (-54/31), j == (12/31)], [i == (-32/31), j == (45/31)], [i ==
> (45/31), j == (-10/31)], [i == -7/5*j + 1, (-10/31) < j, j <
> (45/31)], [i == -9/2*j, (-10/31) < j, j < (12/31)], [i == 2/3*j -
> 2, (12/31) < j, j < (45/31)], [max(2/3*j - 2, -9/2*j) < i, i
> < -7/5*j + 1, (-10/31) < j, j < (45/31)]]
>
> Is there any way to get the intersection of the previous set with
> ZZ^2?, or a command to solve the system over the integers?
>
> Thanks,
>
> Diego
>
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