This is "fixed" now. Also I added a lot of new functions (mostly requested by Kiran but also Suzuki groups and a few others) to permgroup.py and started a new module cubegroup.py for dealing with the Rubik's cube group.
I say "fixed" because I failed to find an elegant solution. It seems most reasonable, as you suggest in your email, to make a CyclotomicField the default base_ring, instead of CC (which is currently the situation). The default base_ring in my "fixed" code is hackish because I cannot see a natural way of declaring the optional parameter base_ring to be the CyclotomicField of the correct order. What I did was declare the default to be something completely idiotic, say ZZ. Then I test to see if base_ring==ZZ, in which case I change it to the CyclotomicField of the correct order. The problem is that def __init__(self, G, names="X", base_ring=CyclotomicField(prod(G.invariants()))): is *illegal* (the second G occurrance is the problem). If this case be corrected somehow, then my contortions can be removed. If you or anyone else can see any way around this, please let me know. +++++++++++++++++++++++++++++++++++++++++++++++++ William Stein wrote: > David, > > I was looking at DualAbelianGroup. I'm very surprised you made it map to > floating point complex numbers, at least for finite groups. It would > make > way more sense to make to a cyclotomic field instead, since everything > would > be exact then. That's how I define Dirichlet characters, which are the > dual group of (Z/nZ)^*. (Actually, with Dirichlet characters, one > can also > map to CC if desired -- it's an option.) > > William > > > sage: G.<a> = DirichletGroup(11) > sage: a(2) > zeta10 > > sage: parent(a(2)) > Cyclotomic Field of order 10 and degree 4 > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@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-support URLs: http://sage.math.washington.edu/sage/ and http://sage.scipy.org/sage/ -~----------~----~----~----~------~----~------~--~---
