#21000: wrong result for pari minpoly
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Reporter: vdelecroix | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-7.3
Component: interfaces | Resolution:
Keywords: | Merged in:
Authors: | Reviewers:
Report Upstream: Reported upstream. No | Work issues:
feedback yet. |
Branch: | Commit:
Dependencies: | Stopgaps:
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Description changed by vdelecroix:
Old description:
> {{{
> sage: R.<x> = ZZ[]
> sage: q = x^24 - 12*x^23 + 70*x^22 - 264*x^21 + 757*x^20 - 1872*x^19 +
> 4258*x^18 - 8796*x^17 + 15922*x^16 - 24900*x^15 + 33886*x^14 - 40608*x^13
> + 43117*x^12 - 40608*x^11 + 33886*x^10 - 24900*x^9 + 15922*x^8 - 8796*x^7
> + 4258*x^6 - 1872*x^5 + 757*x^4 - 264*x^3 + 70*x^2 - 12*x + 1
> sage: pari(1).Mod(q).minpoly()
> x - 1
> sage: pari(1+x-x).Mod(q).minpoly()
> x
> }}}
> This is reproducible in a gp console
> {{{
> ? q = x^24 - 12*x^23 + 70*x^22 - 264*x^21 + 757*x^20 - 1872*x^19 +
> 4258*x^18 - 8796*x^17 + 15922*x^16 - 24900*x^15 + 33886*x^14 - 40608*x^13
> + 43117*x^12 - 40608*x^11 + 33886*x^10 - 24900*x^9 + 15922*x^8 - 8796*x^7
> + 4258*x^6 - 1872*x^5 + 757*x^4 - 264*x^3 + 70*x^2
> ? minpoly(Mod(1, q))
> %2 = x - 1
> ? minpoly(Mod(1+x-x, q))
> %3 = x
> }}}
>
> Original report
>
> https://groups.google.com/forum/#!topic/sage-devel/GfanbBRor6M
New description:
{{{
sage: R.<x> = ZZ[]
sage: q = x^24 - 12*x^23 + 70*x^22 - 264*x^21 + 757*x^20 - 1872*x^19 +
4258*x^18 - 8796*x^17 + 15922*x^16 - 24900*x^15 + 33886*x^14 - 40608*x^13
+ 43117*x^12 - 40608*x^11 + 33886*x^10 - 24900*x^9 + 15922*x^8 - 8796*x^7
+ 4258*x^6 - 1872*x^5 + 757*x^4 - 264*x^3 + 70*x^2 - 12*x + 1
sage: pari(1).Mod(q).minpoly()
x - 1
sage: pari(1+x-x).Mod(q).minpoly()
x
}}}
This is reproducible in a gp console
{{{
? q = x^24 - 12*x^23 + 70*x^22 - 264*x^21 + 757*x^20 - 1872*x^19 +
4258*x^18 - 8796*x^17 + 15922*x^16 - 24900*x^15 + 33886*x^14 - 40608*x^13
+ 43117*x^12 - 40608*x^11 + 33886*x^10 - 24900*x^9 + 15922*x^8 - 8796*x^7
+ 4258*x^6 - 1872*x^5 + 757*x^4 - 264*x^3 + 70*x^2 - 12*x + 1;
? minpoly(Mod(1, q))
%2 = x - 1
? minpoly(Mod(1+x-x, q))
%3 = x
}}}
Original report
https://groups.google.com/forum/#!topic/sage-devel/GfanbBRor6M
--
--
Ticket URL: <https://trac.sagemath.org/ticket/21000#comment:7>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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