On Jun 23, 2:52 pm, David Joyner <[email protected]> wrote: > On Thu, Jun 23, 2011 at 2:40 PM, mmarco <[email protected]> wrote: > > I am trying to write an implementation of the Braid group in sage, and > > i am finding more dificulties than expected. The reason is that the > > categories that would be involved have very few implemented objects. > > For instance, the first very basic functionality i am implementing is > > just the naive free group arithmetic (with lists of integers). So i > > wonder if there is not implementation of the free group in sage > > already done (i have looked for it, to no avail). > > I think free groups are not yet implemented. It would be nice to have them. > They are of course in GAP (and GAP does have a braid > groups package). >
http://www.sagemath.org/doc/reference/sage/categories/coxeter_groups.html seems helpful. Maybe make an Artin group category? David, do you think the GAP version would be too hard to wrap (and play nicely with our current groups)? We don't even seem to have free Abelian groups, really, though they are implicit several places, like in multiplicative Abelian groups and presumably the new additive class. > > > Another question i wonder is if the category framework would give > > support to group actions; and if it doesn't, which would be the > > apropriate aproach to implement them. I think it should - for instance, there is currently work on group actions on integer vectors. - kcrisman -- 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
