#17720: failing primary decomposition with extension field coefficients
--------------------------------+------------------------
Reporter: jakobkroeker | Owner:
Type: defect | Status: new
Priority: major | Milestone: sage-6.5
Component: interfaces | Resolution:
Keywords: Singular | Merged in:
Authors: | Reviewers:
Report Upstream: N/A | Work issues:
Branch: | Commit:
Dependencies: | Stopgaps: todo
--------------------------------+------------------------
Description changed by jakobkroeker:
Old description:
> The following bugs are likely Singular interface bugs (have to
> investigate):
> since the same examples run using shipped Singular behave differently
>
> It may also relate to Singular's variable shadowing issue, see next
> ticket
>
> 0. working example:
> {{{
> sage: R.<b>=QQ[]
> sage: K.<b>=QQ.extension(b^2-b-1)
> sage: r.<x,z>=K[]
> sage: I=r.ideal(z)
> sage: L = I.primary_decomposition("gtz")
> sage: [ J.gens() for J in L]
> #[[z]]
> }}}
> 1. example with wrong result:
> {{{
> sage: R.<p>=QQ[]
> sage: K.<p>=QQ.extension(p^2-p-1)
> sage: r.<x,z>=K[]
> sage: I=r.ideal(z)
> sage: L = I.primary_decomposition("gtz") # wrong!
> sage: [ J.gens() for J in L]
> #[[0, 0]]
> }}}
> 2. crashing example:
> {{{
> sage: R.<p>=QQ[]
> sage: K.<p>=QQ.extension(p^2-p-1)
> sage: r.<x,z>=K[]
> sage:
> sage: I=r.ideal(z)
> sage: I.primary_decomposition()
> #RuntimeError: Error in Singular function call 'primdecSY':
> # identifier pr not found in RH
> # error occurred in or before primdec.lib::algeDeco line 2732: `
> list pr=imap(RH,pr);`
> # leaving primdec.lib::algeDeco
> # leaving primdec.lib::primdecSY
> }}}
>
> corresponding Singular code:
> {{{
> LIB("primdec.lib");
> ring rng = (0,p),(x,z), dp;
> minpoly = p^2-p-1;
> ideal I = z;
> primdecGTZ(I);
>
> LIB("primdec.lib");
> ring rng = (0,b),(x,z), dp;
> minpoly = b^2-b-1;
> ideal I = z;
> primdecGTZ(I);
>
> }}}
New description:
The following bugs are likely Singular interface bugs (have to
investigate):
since the same examples run using shipped Singular behave differently
It may also relate to Singular's variable shadowing issue, see ticket
#17721
0. working example:
{{{
sage: R.<b>=QQ[]
sage: K.<b>=QQ.extension(b^2-b-1)
sage: r.<x,z>=K[]
sage: I=r.ideal(z)
sage: L = I.primary_decomposition("gtz")
sage: [ J.gens() for J in L]
#[[z]]
}}}
1. example with wrong result:
{{{
sage: R.<p>=QQ[]
sage: K.<p>=QQ.extension(p^2-p-1)
sage: r.<x,z>=K[]
sage: I=r.ideal(z)
sage: L = I.primary_decomposition("gtz") # wrong!
sage: [ J.gens() for J in L]
#[[0, 0]]
}}}
2. crashing example:
{{{
sage: R.<p>=QQ[]
sage: K.<p>=QQ.extension(p^2-p-1)
sage: r.<x,z>=K[]
sage:
sage: I=r.ideal(z)
sage: I.primary_decomposition()
#RuntimeError: Error in Singular function call 'primdecSY':
# identifier pr not found in RH
# error occurred in or before primdec.lib::algeDeco line 2732: ` list
pr=imap(RH,pr);`
# leaving primdec.lib::algeDeco
# leaving primdec.lib::primdecSY
}}}
corresponding Singular code:
{{{
LIB("primdec.lib");
ring rng = (0,p),(x,z), dp;
minpoly = p^2-p-1;
ideal I = z;
primdecGTZ(I);
LIB("primdec.lib");
ring rng = (0,b),(x,z), dp;
minpoly = b^2-b-1;
ideal I = z;
primdecGTZ(I);
}}}
--
--
Ticket URL: <http://trac.sagemath.org/ticket/17720#comment:1>
Sage <http://www.sagemath.org>
Sage: Creating a Viable Open Source Alternative to Magma, Maple, Mathematica,
and MATLAB
--
You received this message because you are subscribed to the Google Groups
"sage-trac" group.
To unsubscribe from this group and stop receiving emails from it, send an email
to [email protected].
To post to this group, send email to [email protected].
Visit this group at http://groups.google.com/group/sage-trac.
For more options, visit https://groups.google.com/d/optout.
