> > doc/en/constructions/rings.rst +58
> >    sage: R = singular.ring(97, '(a,b,c,d)', 'lp')
> >    sage: I = singular.ideal(['a+b+c+d', 'ab+ad+bc+cd',
> > 'abc+abd+acd+bcd', 'abcd-1'])
> >    sage: R
> > Expected:
> >    //   characteristic : 97
> >    //   number of vars : 4
> >    //        block   1 : ordering lp
> >    //                  : names    a b c d
> >    //        block   2 : ordering C
> > Got:
> >    //   characteristic : 97
> >    //   number of vars : 4
> >    //        block   1 : ordering lp
> >    //                  : names    abcd
> >    //        block   2 : ordering C
> > * The sage spkg don't have a patch to separate the names, so I am
> > assuming it is a minor change in singular
>
> looks safe

Yes, this was fixed in Singular recently, I assume Mandriva only needs to 
update to the newest upstream release.

> > rings/polynomial/toy_d_basis.py +171
> >        sage: from sage.rings.polynomial.toy_d_basis import gpol
> >        sage: P.<x, y, z> = PolynomialRing(IntegerRing(), 3, order='lex')
> >        sage: f = x^2 - 1
> >        sage: g = 2*x*y - z
> >        sage: gpol(f,g)
> > Expected:
> >    x^2*y - y
> > Got:
> >    x^2*y - x*z + y
> > * Not sure what is the cause, neither if this is an alternate correct
> > result...]
>
> Martin -- any thoughts?

Here is what gpol does

 a1,a2 = g1.lc(),g2.lc()# a1 = 1, a2 = 2
 a, c1, c2 = xgcd(a1,a2) # (1,0,1) -> this is not unique
 t1,t2 = g1.lm(), g2.lm() # x^2, x*y
 t = t1.parent().monomial_lcm(t1,t2) # x^2*y
 s1,s2 = t//t1, t//t2 # y, x
 return c1*s1*g1 + c2*s2*g2 # 0*y*g1 + 1*x*g2

I guess xgcd changed (e.g. (1,-1,1)) and thus the result is different. So it 
seems also correct.

Cheers,
Martin

-- 
name: Martin Albrecht
_pgp: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99
_otr: 47F43D1A 5D68C36F 468BAEBA 640E8856 D7951CCF
_www: http://www.informatik.uni-bremen.de/~malb
_jab: [email protected]



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