hi there, sorry if this is not really sage-related (it is in a way).
So David, i'm currently reading your book "adventures in group theory", and i'm thoroughly enjoying it. I'm sure it will also be of great help when i finally teach sage in my university (the switch from maple is about to happen, maybe next year!) there is something puzzling me though, if i may say so... It's the movement M_R. As you describe it, it moves the middle slice... therefore moving the central facets, so strictly speaking it's certainly not a move in the cube's group. I understand that you can almost get the same effect by moving the left and right faces in the opposite direction, so something like LR^-1 if i get the orientations right. However, there is a difference, in that you need to look at the cube from another angle if you want to get the feeling that it's the middle slice that's just moved. In doing so, the next moves U, F ... become ambiguous to me, as i don't know what the "front" is anymore. i've tried this with sage, following section 5.1.1, p287, trying to "flip the top edges uf, ub": sage: rubik = CubeGroup() sage: r= rubik.R() sage: l= rubik.L() sage: u= rubik.U() sage: d= rubik.D() sage: f= rubik.F() sage: b= rubik.B() sage: mr = r^(-1)*l sage: flip= (mr*u)^3*u*(mr^(-1)*u)^3*u sage: P= rubik.plot3d_cube(flip); show(P) the result is a bit of a mess. what am i getting wrong ? thanks ! Pierre --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
