Hi Simon, On Fri, Nov 25, 2011 at 06:58:15AM -0800, Simon King wrote: > After some "serach_src", it seems to me that there are no SAGBI bases > in Sage. > > Are there plans to add them? Is there free software (with appropriate > licence) that one could build upon? If I remember correctly, Nicolas > Thiéry used SAGBI bases for computing invariant rings of permutation > groups. Perhaps he can give a pointer?
There seems to be SAGBI implementations in: - Singlular (http://www-salsa.lip6.fr/~jcf/Papers/ISSAC09a.pdf mentions a sagbi.lib) - CoCoA: http://www.apcocoa.org/wiki?title=Category:Package_sagbi And I would assume there is one in Macaulay, possibly written by Harrisson Tsai. But this might be a wide guess. As for my implementation in MuPAD-Combinat, the thing is that I used them in a special context (invariants of permutation groups) where the algorithmic was kind of reversed: I had an a priori description of the initial algebra is, but wanted both the generators of that initial ideal together with certain relations (to then go further with SAGBI-Groebner bases), whereas usually one has just generators for the algebra and want to get the initial ideal. Still, I plan to port this over someday; and it should be fairly quick now that Nicolas has implemented the generation of monomials up to an isomorphism. Cheers, Nicolas -- Nicolas M. Thiéry "Isil" <nthi...@users.sf.net> http://Nicolas.Thiery.name/ -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
