On Thu, Feb 16, 2012 at 7:47 PM, Chris Smith <smi...@gmail.com> wrote:
> The docstring notes:
>
> * when the system is linear
>
> * with a solution
>
> >>> solve([x - 3], x)
> {x: 3}
> >>> solve((x + 5*y - 2, -3*x + 6*y - 15), x, y)
> {x: -3, y: 1}
> >>> solve((x + 5*y - 2, -3*x + 6*y - 15), x, y, z)
> {x: -3, y: 1}
> >>> solve((x + 5*y - 2, -3*x + 6*y - z), z, x, y)
> {x: -5*y + 2, z: 21*y - 6}
>
> * without a solution
>
> >>> solve([x + 3, x - 3])
>
> So you are dealing with a linear system that has no solution. An empty
> list might be returned if there were no solutions satisfying the
> requirements (assumptions, etc...) but for this system there is no
> solution so None is returned.
>
So would it be accurate to say that None means that we know that there
are no solutions and [] means that we just didn't find any?
Aaron Meurer
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