#17721: variable shadowing: major design flaw in Singular
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Reporter: jakobkroeker | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.5
Component: packages: standard | Resolution:
Keywords: Singular | Merged in:
Authors: | Reviewers:
Report Upstream: Reported upstream. Developers | Work issues:
acknowledge bug. | Commit:
Branch: | Stopgaps: todo
Dependencies: #17720 |
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Comment (by jakobkroeker):
translated example from www.singular.uni-kl.de:8002/trac/ticket/677 :
{{{
sage: K0=QQ
sage: R0.<p>=K0[]
sage: K.<p>=QQ.extension(p^2-p-1)
sage: R1.<w,x,y,z>=K[]
sage: I =
R1.ideal((-12*p-6)*w^5+(16*p+8)*w^3*x^2+(-4*p-2)*w*x^4+(16*p+8)*w^3*y^2+(-8*p-4)*w*x^2*y^2+(-4*p-2)*w*y^4+(16*p+8)*w^3*z^2+(-8*p-4)*w*x^2*z^2+(-8*p-4)*w*y^2*z^2+(-4*p-2)*w*z^4,(8*p+4)*w^4*x+(-8*p-4)*w^2*x^3+(-8*p-4)*w^2*x*y^2+(-48*p-32)*x^3*y^2+(8*p+8)*x*y^4+(-8*p-4)*w^2*x*z^2+(16*p+16)*x^3*z^2+(64*p+32)*x*y^2*z^2+(-24*p-16)*x*z^4,(8*p+4)*w^4*y+(-8*p-4)*w^2*x^2*y+(-24*p-16)*x^4*y+(-8*p-4)*w^2*y^3+(16*p+16)*x^2*y^3+(-8*p-4)*w^2*y*z^2+(64*p+32)*x^2*y*z^2+(-48*p-32)*y^3*z^2+(8*p+8)*y*z^4,(8*p+4)*w^4*z+(-8*p-4)*w^2*x^2*z+(8*p+8)*x^4*z+(-8*p-4)*w^2*y^2*z+(64*p+32)*x^2*y^2*z+(-24*p-16)*y^4*z+(-8*p-4)*w^2*z^3+(-48*p-32)*x^2*z^3+(16*p+16)*y^2*z^3)
sage: L = I.primary_decomposition("gtz")
sage: IJ = I
sage: for J in L:
....: IJ = IJ.intersection(J)
....:
sage: IJ == I
False
}}}
--
Ticket URL: <http://trac.sagemath.org/ticket/17721#comment:3>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
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