On 10/13/07, Mike Hansen <[EMAIL PROTECTED]> wrote: > > I just saw Robert's ticket about implementing / wrapping braid groups > in SAGE ( http://www.sagetrac.org/sage_trac/ticket/876 ) which is > pretty coincidental since I was thinking about the exact same thing > before I went to bed last night. I wrote an email to Nikos > Apostolakis who had expressed interest in this on sage-support in June > to see if he was still interested.
Please also check out the GAP package braid http://sage.math.washington.edu/home/wdj/gap/braid.tar.gz written by K. Magaard, S. Shpectorov and H. Voelklein, and HAP, which I think has some briad-related stuff but I can't find it right now. > > GAP3 had support for braid groups provided by the "share package" > CHEVIE. Unfortunately, when the change to GAP4 was made, this was > never ported over. As David Joyner mentioned, one possibility is to > have a (optional) GAP3 package from which the functionality could be > wrapped. Another possibility is to port the GAP3 chevie code over to > GAP4. I do not know how much of an undertaking this would be because > my familiarity with GAP programming is almost non-existent. The third > possibility would be to port chevie directly over to SAGE; I looked at > the code for chevie, and this is definitely doable. It would however > take a bit of time -- it's about 6000 lines of GAP code and about 2000 > lines of comments. I spoke with Frank Luebeck while in Germany last month. While a nice guy and a very talented mathematician and programmer, Frank is very very particular about the code he releases. The Chevie port to GAP4 is basically finished and in my opinion should be released. It would be a complete waste of time to work on GAP3 stuff. I told Frank that it should be released now and he simply disagrees. (It is his work on this for the most part, though he does have co-authors.) He said it is high on his priority list to go through the code and carefully bug-check it as soon as possible. However, he has not ported the Hecke algebra section of Chevie and has no immediate plans to do so. > > It would be good to have a framework for root systems and the like > that all of these things can fit into. This may be helpful in that > aspect: http://mupad-combinat.sourceforge.net/Wiki/RootSystems > > --Mike > > > > --~--~---------~--~----~------------~-------~--~----~ 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/ -~----------~----~----~----~------~----~------~--~---
