#12745: Coercion problem with Algebraic Real Field
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Reporter: davidloeffler | Owner: AlexGhitza
Type: defect | Status: needs_work
Priority: major | Milestone: sage-6.1
Component: symbolics | Resolution:
Keywords: | Merged in:
Authors: Marc Mezzarobba | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
u/mmezzarobba/12745-SR_to_AA | 8f74a7b8af077e27beff9b6f4b663d9deeea728b
Dependencies: | Stopgaps:
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Comment (by mmezzarobba):
I thought it would be a quick fix, but in fact there are at least two
deeper issues here:
* Simplification of symbolic powers of negative numbers is completely
broken, with inconsistent interpretations all over the place (see, e.g.,
#15605).
* Rational powers of negative numbers in `AA` are defined to choose real
roots when possible (see the docstring of `sage.rings.qqbar`)
{{{
sage: AA((-1)^(1/3))
-1
sage: AA(-1)^(1/3)
-1
}}}
These semantics do not extend well to real expressions with non-real
complex subexpressions.
I'm giving up, at least for now.
--
Ticket URL: <http://trac.sagemath.org/ticket/12745#comment:4>
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