On 19 August 2010 09:50, Mitesh Patel <qed...@gmail.com> wrote: > On 08/18/2010 07:13 PM, William Stein wrote: >> On Wed, Aug 18, 2010 at 4:18 AM, David Kirkby <david.kir...@onetel.net> >> wrote: >>> On 18 August 2010 11:33, John Cremona <john.crem...@gmail.com> wrote: >>>> On 17 August 2010 23:31, William Stein <wst...@gmail.com> wrote: >>> >>>>>>> It would be a student project to reimplement Mark W's algorithm (Here: >>>>>>> http://www.emis.ams.org/journals/EM/expmath/volumes/11/11.4/pp487_502.pdf) >>>>> >>>>> This is what should happen. After somebody implements his algor >>>>> in Sage, then >>>>> we can (re)move Sympow. Here's a trac ticket: >>>>> >>>>> http://trac.sagemath.org/sage_trac/ticket/9758 >>>>> >>> >>> It would be good to state on the ticket what level of student project >>> this is (undergrad, postgrad), and the skill set needed (C, Python >>> etc). I expect you would prefer it in Python, though I think >>> personally a C implementation like Marks, which you can easily call >>> from Python, would be more beneficial to the scientific community in >>> general - not everyone is using Sage/Python. >>> >>> I know if I were a student, I'd prefer a bit more information on that >>> trac ticket. >> >> Good idea -- I've posted some stuff there. > > Would a project to rewrite genus2reduction.c [1] as part of the Sage > library be at a similar level? Is there a paper(s) on the algorithm? > > [1] This is part of the genus2reduction spkg, which does not have the > same build problems as SYMPOW, as far as I'm aware. The motivation here > would be, perhaps, to get some experience with PARI, Cython, and > (hyper)elliptic curves. We'd also reduce very slightly our spkg > maintenance burden. >
I think the relavant paper from Liu's web page (http://www.math.u-bordeaux.fr/~liu/) is this: Qing Liu : Conducteur et discriminant minimal de courbes de genre 2 Compositio Math., 94 (1994), 51-79 Unfortunately, unless I am mistaken (and I hope so!) there are no genus 2 experts currently working on (or with) Sage. The credit for his program goes to various people (Cohen, Poonen, Schaefer, Stoll and more) as well as himself. I think that this would be considerably harder than reimplementing the modular degree part of sympow. Note, in particular, that Liu's algorithm only gives the odd part of the conductor of a genus 2 curve. Even after 15 years or so, no-one has ever worked out the details for p=2. I regularly ask genus 2 people (if you see what I mean; it sounds a very uncomfortable state to be in) about this and they usually throw up their hands saying there are hundreds of cases to be considered. I don't think I have the expertise to do that, or supervise someone else to do it. John > -- > 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 > -- 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
