Re: [sage-devel] (x^6+y^9)%(x^3-y^2-1) == x^12*y - 4*x^9*y + ...

2023-03-10 Thread Georgi Guninski
Many thanks for all replies. GMS suggested to use Ideal.reduce(), but from the documentation: "Requires computation of a Groebner basis, which can be a very expensive operation" I suspected that polynomial division is significantly more cheap than groebner basis. -- You received this message be

Re: [sage-devel] (x^6+y^9)%(x^3-y^2-1) == x^12*y - 4*x^9*y + ...

2023-03-10 Thread Dima Pasechnik
On Fri, 10 Mar 2023, 09:53 Georgi Guninski, wrote: > Many thanks for all replies. > > GMS suggested to use Ideal.reduce(), but from the documentation: > "Requires computation of a Groebner basis, which can be a very > expensive operation" > > I suspected that polynomial division is significantly

Re: [sage-devel] (x^6+y^9)%(x^3-y^2-1) == x^12*y - 4*x^9*y + ...

2023-03-10 Thread G. M.-S.
Hi Georgi. In the case of a principal ideal, to get a Gröbner basis the only thing you may need is making the generator monic, so there is almost nothing to do. Then you do an ordered division of the other polynomial by this one, which is straightforward. HTH, Guillermo On Fri, 10 Mar 2023 at 1

[sage-devel] Possibly incorrect result in groebner basis over the integers

2023-03-10 Thread Georgi Guninski
I think grobner basis which contain non-zero constant and polynomials is a bug. sage: K.=ZZ[] sage: l=[x^2+y^2+x+4,x^2+y^2+4*y+2,x^2-13*y^2+x] sage: I=Ideal(l);gb=I.groebner_basis();gb [y^2 + 4*y + 198, x + 1036*y + 2, 8*y + 544, 1040] -- You received this message because you are subscribed to

Re: [sage-devel] Possibly incorrect result in groebner basis over the integers

2023-03-10 Thread G. M.-S.
This result is correct, as you are working over ℤ. If you try over ℚ, you will get [1]. Guillermo On Fri, 10 Mar 2023 at 11:57, Georgi Guninski wrote: > I think grobner basis which contain non-zero constant and polynomials > is a bug. > > sage: K.=ZZ[] > sage: l=[x^2+y^2+x+4,x^2+y^2+4*y+2,x^2-1

Re: [sage-devel] Possibly incorrect result in groebner basis over the integers

2023-03-10 Thread Emmanuel Briand
Not a bug, but a (nice) feature: Gröbner bases for rings of polynomials with integers coefficients, documented in: https://doc.sagemath.org/html/en/reference/polynomial_rings/sage/rings/polynomial/multi_polynomial_ideal.html El vie, 10 mar 2023 a las 11:57, Georgi Guninski () escribió: > I thin