On Mon, Jan 19, 2009 at 1:40 AM, John H Palmieri <jhpalmier...@gmail.com> wrote: > > I have a first draft of a module which implements simplicial > complexes, chain complexes, and their homology. It isn't perfect: it > is limited by Sage's abilities to deal with modules over arbitrary > commutative rings, or at least by my knowledge of Sage's abilities. > Thus for example, you can define a chain complex over a polynomial > ring on one or several variables, but you probably can't compute its > homology very reliably. > > I would appreciate comments, and eventually I hope to submit it to the > trac server. > > (I tried searching the various Sage groups to see if anyone was > working on similar stuff and didn't find anything. I hope I'm not > stepping on any toes.)
You are not stepping on any toes AFAIK but doesn't the GAP package HAP implement something like this? http://www.gap-system.org/Packages/hap.html Maybe most of what he does requires a group action but there is this example: http://hamilton.nuigalway.ie/Hap/www/SideLinks/About/aboutTensorSquare.html (Not that I know a lot about the subject but isn't this the kind of homology you are dealing with?) Anyway, he told me that there are some resolutions which are "exponentially slow" and some which are not so slow and I believe he has thought long and hard about computing such things as quickly as possible. So it might be worth a look if you don't know it already. In any case, it's nice to have another version, especially in Python/Sage! > > See the file 'http://sage.math.washington.edu/home/palmieri/ > homology.patch' for more. > > John > > > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
