One difference is that in the multivariable case, having the return value in the ring with fewer variables would require that ring to be created. I don't know how much of an over head that would be. Also, whether Sage would automatically be ably work with the three subrings (say) k[x,y], k[x,z], k[y,z] of k[x,y,z] in a way which was mathematically correct and transparent, and also efficient.
I have CC'd sage-algebra. John On Sun, Feb 20, 2011 at 6:09 AM, mmarco <[email protected]> wrote: > I have recently opened track ticket 10799 solving some problems with > coumputing resultants in univariate polynomial rings. Now i plan to > implement the .discriminant() method for polynomials in multivariable > rings. But i have a doubt now. The method .resultant() returns a > polynomial in the same ring in the case of multivariable polynomials. > But the same method returns an object in the base ring for the case of > univariate polynomials (and also does de .discriminant() ) > > I think that a unified criterion would be desirable. And i would > prefear the one that now exists for univariate polynomials. > > So, my question is: do you think that if f and g are polynomials in > K[x,y,z], f.resultant(g,y) should live in K[x,y,z] or in K[x,z]? And > the same question for f.discriminant() > > -- > To post to this group, send an email to [email protected] > To unsubscribe from this group, send an email to > [email protected] > For more options, visit this group at > http://groups.google.com/group/sage-devel > URL: http://www.sagemath.org > -- To post to this group, send an email to [email protected] To unsubscribe from this group, send an email to [email protected] For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
