On 2013-10-01, John Lapeyre <lapeyre.math122a at gmail.com> wrote:
> I see three possible interpretations of this example
> (are there more ?) :
>
> 1. (-1)^(1/6) means one particular root of z^6=-1
> (e.g. the principal root). solve gave the
> correct answer. But perhaps solve should have
> applied rectform itself.
>
> 2. the meaning of (-1)^(1/6) depends on the context.
> eg if it appears at the top-level of expressions
> in a list of three elements, then it means
> the same root in each case, maybe a specific
> root. This is obviously problematic.
>
> 3. (-1)^(1/6) means any one of the the six roots,
> or maybe all of them. It's up to the user to
> decide. In this case, solve gave an incorrect answer
> and this is a bug in solve.
I think it's a bug in solve that the result is ambiguous.
If we can't even solve a simple equation unambiguously, who knows what
will happen in complicated problems.
best
Robert Dodier