#14485: Creation of a polynomial over QQbar
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Reporter: tmonteil | Owner: malb
Type: defect | Status: new
Priority: major | Milestone: sage-5.10
Component: commutative algebra | Resolution:
Keywords: QQbar, polynomial | Work issues:
Report Upstream: N/A | Reviewers:
Authors: | Merged in:
Dependencies: | Stopgaps:
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Description changed by tmonteil:
Old description:
> Here is the issue: there is no problem buildind a polynomial over AA:
>
> {{{
> sage: R = AA[x]
> sage: P = R(x^6+x^5+x^4-x^3+x^2-x+2/5)
> }}}
>
> But the same operation does not work on QQbar:
>
> {{{
> sage: S = QQbar[x]
> sage: Q = S(x^6+x^5+x^4-x^3+x^2-x+2/5)
> Traceback (most recent call last)
> ...
> NotImplementedError: symbol
> }}}
>
> Hovewer, this workaround works:
>
> {{{
> sage: Q = P.change_ring(QQbar)
> }}}
>
> Weird isn't it ?
New description:
Here is the issue: there is no problem buildind a polynomial over AA:
{{{
sage: R = AA[x]
sage: P = R(x^6+x^5+x^4-x^3+x^2-x+2/5)
}}}
But the same operation does not work on QQbar:
{{{
sage: S = QQbar[x]
sage: Q = S(x^6+x^5+x^4-x^3+x^2-x+2/5)
Traceback (most recent call last)
...
NotImplementedError: symbol
}}}
Hovewer, this workaround works:
{{{
sage: Q = P.change_ring(QQbar)
}}}
Moreover the following works :
{{{
sage: S.<x> = PolynomialRing(QQbar,'x')
sage: Q = S(x^6+x^5+x^4-x^3+x^2-x+2/5)
sage: S == QQbar[x]
True
}}}
Weird isn't it ?
--
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Ticket URL: <http://trac.sagemath.org/sage_trac/ticket/14485#comment:1>
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