On Sunday 27 February 2011, dmharvey wrote:
> Hi,
> 
> sage: R.<x0,x1,x2,x3> = PolynomialRing(QQ)
> sage: f = x0^2*x1 + x1^2*x2 + x2^2*x3 + x3^2*x0
> sage: (f0, f1, f2, f3) = [f.derivative(v) for v in [x0, x1, x2, x3]]
> sage: I = R.ideal(f0, f1, f2, f3)
> sage: h = x0^5
> sage: h in I
> sage: True

Hi David,

sage: R.<x0,x1,x2,x3> = PolynomialRing(QQ)
sage: f = x0^2*x1 + x1^2*x2 + x2^2*x3 + x3^2*x0
sage: (f0, f1, f2, f3) = [f.derivative(v) for v in [x0, x1, x2, x3]]
sage: I = R.ideal(f0, f1, f2, f3)
sage: h = x0^5
sage: h.lift(I)
[-x0^2*x2 - 4/15*x0*x1*x3, x0^3 + 8/15*x1^2*x3 + x2*x3^2, -16/15*x1*x2*x3, 
2/15*x1*x3^2]

sage: h.lift(I.gens())
[-x0^2*x2 - 4/15*x0*x1*x3, x0^3 + 8/15*x1^2*x3 + x2*x3^2, -16/15*x1*x2*x3, 
2/15*x1*x3^2]

sage: h.lift(I.groebner_basis())
[0, 0, 0, 0, x0*x2, x0^3, -2*x0^2*x2, 0, 0]

sage: sum(map(prod,zip(I.groebner_basis(),h.lift(I.groebner_basis()))))
x0^5

Cheers,
Martin

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name: Martin Albrecht
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