#11941: Solve and assumptions too aggressive with cube root of negative numbers
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Reporter: kcrisman | Owner: burcin
Type: defect | Status: new
Priority: major | Milestone: sage-4.8
Component: symbolics | Keywords:
Work_issues: | Upstream: N/A
Reviewer: | Author:
Merged: | Dependencies:
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Comment(by kcrisman):
Replying to [comment:6 mboratko]:
> It seems that sage sets domain: complex (I was made aware of this by
burcin in IRC). You do get this result as follows:
Yes, we do, but I didn't bother checking that. Good work.
So of course now the question becomes what the "right" thing to do is? I
don't think we want to set and unset `domain:real/complex` in Maxima every
time we use `solve`, because presumably this would break other things.
Or? At any rate we definitely need to keep `domain:complex` in general,
if I recall correctly other problems that occur without it.
{{{
(%i1) (-1)^(1/3);
(%o1) - 1
(%i2) domain:complex;
(%o2) complex
(%i3) (-1)^(1/3);
1/3
(%o3) (- 1)
}}}
Typically we would want the latter answer, e.g in
{{{
sage: a = (-1)^(1/3)
sage: a.simplify()
(-1)^(1/3)
}}}
--
Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/11941#comment:8>
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