> To implement M_R in Sage would be non-trivial, since it > is a pair of moves followed by a solid cube rotation. > The rotation changes *all* the moves which follow it. > So to implement X*M_R*Y (reading left-to-right) in Sage > you'd have to change Y.
I see! In a sense i was sort of right. Now it seems surprising that the "cube group" is not defined to include 3 full rotations of the cube on top of the 6 basic moves. I guess this is the easiest way to work with M_R, and use your formulae. And then in order to get back to the original group and obtain some pictures, one would associate, to any element of this larger group, an element of the cube group by peforming a bunch of rotations to put the central faces back in their place. Easier said than done perhaps. I guess the larger group is a semi direct product of the cube group by S_4. > Glad you like the book! 50% of the royalties go directly to Sage > and the remainder go to EII (earthisland.org). it's great ! when asked why algebra is important and useful, or what groups are, i used to mumble something about the rubik's cube as an application, but truly i had no idea what the connection really was ! i wish i could teach group theory from your book, but unfortunately around here in france we usually go for fully bourbakized accounts. I have a colleague who, after giving the definition of an abelian group, went "Example 1. The trivial group is abelian". You get the picture. I myself was a student in england so i'm a bit different in this respect... however i'm sure i'll use the book when teaching sage, providing that happens. 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 -~----------~----~----~----~------~----~------~--~---
