Keith, Could you be more precise about what computations you want to do in a quotient of a noncommutative group ring? Do you just want to do basic arithmetic? Do you need to check equality? Do you need abstract structure statements?
-- William On 7/23/07, Martin Albrecht <[EMAIL PROTECTED]> wrote: > To whom it may concern, > > there is plural: http://www.singular.uni-kl.de/Manual/latest/sing_349.htm > > which is shipped with SAGE (though, the interface hasn't been worked on) > > sage: singular.lib('ncalg.lib') > sage: a = singular.makeUsl2() > sage: W = singular.ring(0,'(x,d)','dp') > sage: singular.Weyl() > `sage2` > sage: S = a + W > sage: singular.set_ring(S) > sage: S > > // characteristic : 0 > // number of vars : 5 > // block 1 : ordering dp > // : names e f h > // block 2 : ordering dp > // : names x d > // block 3 : ordering C > // noncommutative relations: > // fe=e*f-h > // he=e*h+2*e > // hf=f*h-2*f > // dx=x*d+1 > > or in terms of SINGULAR/PLURAL directly: > > LIB "ncalg.lib"; > def a = makeUsl2(); // U(sl_2) in e,f,h presentation > ring W = 0,(x,d),dp; > Weyl(); // 1st Weyl algebra in x,d > def S = a+W; > setring S; > S; > ==> // characteristic : 0 > ==> // number of vars : 5 > ==> // block 1 : ordering dp > ==> // : names e f h > ==> // block 2 : ordering dp > ==> // : names x d > ==> // block 3 : ordering C > ==> // noncommutative relations: > ==> // fe=ef-h > ==> // he=eh+2e > ==> // hf=fh-2f > ==> // dx=xd+1 > > Martin > > PS: I don't know much about non-commutative algebra, so I wouldn't know if > your favorite ring is supported by PLURAL. > > > -- > name: Martin Albrecht > _pgp: http://pgp.mit.edu:11371/pks/lookup?op=get&search=0x8EF0DC99 > _www: http://www.informatik.uni-bremen.de/~malb > _jab: [EMAIL PROTECTED] > > > > > -- William Stein Associate Professor of Mathematics University of Washington http://www.williamstein.org --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to [EMAIL PROTECTED] For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://sage.scipy.org/sage/ and http://modular.math.washington.edu/sage/ -~----------~----~----~----~------~----~------~--~---
