From:

~~~ ~~~ Subject:

1) I guess the RLUDFB notation is pretty standard, but the part about

using lower case letters to represent inverses isn't. I find it

pretty distasteful and much prefer using "'". This has the added feature

that you can write: (RLU)' to indicate the inverse if RLU. (I KNOW that

it is just U'L'R', but sometimes one wants to make the distinction.)

2) Yes, lots of things are known about the group and its subgroups.

Start by reading old cube-hackers mail while you wait for your copy

of Singmaster to arrive.

5) Yes, there is an easy way to tell if a cube is solveable without

actually trying it. Here it is:

Three conditions must be true: a) The sum of the rotations of the

corner cubies must be a multiple of 360 or 2 pi (depending on how you

count!). b) The permutation of the faces of the edge cubies must be

even. c) The permutation of all the cubies must be even.

8) Yes, they are real orbits.