#17696: bug in polynomial interface to Singular (in special rings)
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Reporter: jakobkroeker | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.5
Component: interfaces | Resolution:
Keywords: Singular polynomial interface | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps:
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Description changed by jakobkroeker:
Old description:
> It seems that the interface to Singular has a bug,
> see example:
> {{{
> sage: K0=GF(11)
> sage: #K0=QQ
> sage: R0.<b>=K0[]
> sage: K.<b>=K0.extension(b^5+4)
> sage: R1.<zzz>=K[]
> sage: L=FractionField(R1)
> sage: R.<x>=L[]
> sage: f=x^4+1/(b*zzz)
> True
> sage: f._singular_() # where is the fraction 1/(b*zzz) ?
> x^4
> sage: g = R(x^4)
> sage: f==g
> False
>
> }}}
>
> Note that already
> {{{
> sage: (1/(b*zzz))._singular_()
> 0
> }}}
>
> Remarkable is that {{{f = x^4+1/(b)*(1/zzz) }}} is correctly translated
> to Singular:
> {{{
> sage: K0=GF(11)
> sage: #K0=QQ
> sage: R0.<b>=K0[]
> sage: K.<b>=K0.extension(b^5+4)
> sage: R1.<zzz>=K[]
> sage: L=FractionField(R1)
> sage: R.<x>=L[]
> sage: f=x^4+1/(b)*(1/zzz)
> sage: f._singular_()
> -1/(4*zzz)*b^4+x^4
> sage: g = -1/(4*zzz)*b^4+x^4
> sage: f == g
> True
> }}}
>
> Please check if there is a similar issue in other rings than in the
> example above.
>
> @Simon, @Martin:
> should I Ccing someone else or remove you from Cc?
New description:
It seems that the interface to Singular has a bug,
see example:
{{{
sage: K0=GF(11)
sage: #K0=QQ
sage: R0.<b>=K0[]
sage: K.<b>=K0.extension(b^5+4)
sage: R1.<zzz>=K[]
sage: L=FractionField(R1)
sage: R.<x>=L[]
sage: f=x^4+1/(b*zzz)
sage: f._singular_() # where is the fraction 1/(b*zzz) ?
x^4
sage: g = R(x^4)
sage: f==g
False
}}}
Note that already
{{{
sage: (1/(b*zzz))._singular_()
0
}}}
Remarkable is that {{{f = x^4+1/(b)*(1/zzz) }}} is correctly translated to
Singular:
{{{
sage: K0=GF(11)
sage: #K0=QQ
sage: R0.<b>=K0[]
sage: K.<b>=K0.extension(b^5+4)
sage: R1.<zzz>=K[]
sage: L=FractionField(R1)
sage: R.<x>=L[]
sage: f=x^4+1/(b)*(1/zzz)
sage: f._singular_()
-1/(4*zzz)*b^4+x^4
sage: g = -1/(4*zzz)*b^4+x^4
sage: f == g
True
}}}
Please check if there is a similar issue in other rings than in the
example above.
@Simon, @Martin:
should I Ccing someone else or remove you from Cc?
--
--
Ticket URL: <http://trac.sagemath.org/ticket/17696#comment:1>
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