On Tue, May 19, 2009 at 1:36 PM, javier <vengor...@gmail.com> wrote: > > Hi David > > On May 19, 5:51 pm, David Joyner <wdjoy...@gmail.com> wrote: >> 1. you can coerce the coefficients to GF(3) > > Can I? The generators are still distinct in GF(3), but I might lose > elements when I take products (maybe not in this case, I am thinking > about the general problem for an arbitrary Weyl group). Wouldn't do > that unless I have a way to determine the finite field in which things > still are what they should.
sage: s1 = matrix([[-1, 0, 0], [1, 1, 0], [0, 0, 1]]) sage: s2 = matrix([[1, 1, 0], [0, -1, 0], [0, 1, 1]]) sage: s3 = matrix([[1, 0, 0], [0, 1, 1], [0, 0, -1]]) sage: I3 = identity_matrix(GF(3),3) sage: G0 = MatrixGroup([s1*I3,s2*I3,s3*I3]) sage: G0.order() 24 You don't lose elements. > >> 2. You can try G1 = gap(G) and >> G2 = gap(SymmetricGroup(4)) >> and G1.IsomorphismGroups(G2): >> > ..... ..... >> >> sage: G1.IsomorphismGroups(G2) >> >> CompositionMapping( GroupGeneralMappingByImages( SymmetricGroup( >> [ 1 .. 4 ] ), SymmetricGroup( [ 1 .. 4 ] ), [ (1,3,2,4), (1,2,3,4) ], >> [ (1,2,3,4), (1,4,2,3) ] ), <action isomorphism> ) > > That might actually work, but the output is a bit bizarre. Can I see > from there what are the images of my generators, or at least turn the > output into a "true/false" boolean? I'm not sure. Chapter 38 of the GAP reference manual might explain that though. > > Thanks for your answer. > > Javier > > > --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-support@googlegroups.com To unsubscribe from this group, send email to sage-support-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-support URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
