How can group theory be applied to improve Rubik's cube solutions?

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SUMMARY

This discussion focuses on the application of group theory (GT) to enhance solutions for the Rubik's Cube and its variants (2x2, 3x3, 4x4, 5x5). The participant emphasizes the importance of understanding the non-commutative nature of cube moves, illustrated by the example of xy ≠ yx. They propose using "operators" derived from sequences of twists to optimize solving strategies. Recommendations include contacting speedcuber Chris Hardwick and exploring resources like the "Mathematics of the Rubik's Cube" PDF and various online communities for further insights into efficient solving techniques.

PREREQUISITES
  • Basic understanding of group theory concepts
  • Familiarity with Rubik's Cube mechanics and notation
  • Knowledge of permutation and combination principles
  • Experience with speedcubing techniques
NEXT STEPS
  • Research "commutators" and their application in Rubik's Cube solving
  • Explore the "Fewest Move Challenge" for advanced solving strategies
  • Study the "Mathematics of the Rubik's Cube" PDF for theoretical insights
  • Join the Yahoo Speedcubing group for community support and resources
USEFUL FOR

Rubik's Cube enthusiasts, speedcubers, mathematicians interested in practical applications of group theory, and anyone seeking to improve their cube-solving efficiency.

Antiphon
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I've always been fascinated by Rubik's cube. I have developed solutions for it and
all the related cubes 2x2, 3x3, 4x4, 5x5. For me the cube it is to group theory
(of a partcular type of group) what a slide rule is to real arithmetic. Even "laboratory"
might not be too stong a label for it.

For example it's immediately obvious how xy \neq yx. If you turn the front of the cube
and then the right you get a very different set of faces than the right followed by front.
Also, you can discover marvelous "operators" (my terminology) by doing some random
series of twists (abc) followed by a particular twist (Z) then undoing the first
twists (via cba), that is: abcZcba where the letters stand for some particular oriented
twist. What happens is that most of the cube is unperturbed except for some
marvelous little permutation like a twisted corner in place or three swapped edges.

My solutions then consist of applying these "operators" in sequence by inspection
to see which one is "needed" next.

Alas however, I am not formally trained in group theory and I would like
to know: How would one go about using GT to develop a more effective
or efficient solution to something like Rubik's cube? I know it has been
done, but my question is very specifically: Can anyone explain to the group theory novice
(but Rubik's cube expert) how one would actually go about using GT to
devise (more) efficient solutions to such a puzzle?
 
Physics news on Phys.org
find the book by dik winter.
 
Thanks...
 
Hello Antiphoton,

you could contact Chris Hardwick, he is a speedcuber and interested in math too. Go to
www.speedcubing.com > Chris Hardwick's Corner > at the bottom is his e-mail.

Also try the Yahoo Speedcubing group. I'm sure there are also some math interested people there:
http://games.groups.yahoo.com/group/speedsolvingrubikscube/
(You have to sign up and join the group).

P.S. By the way, what's your 3x3 average time?
 
Last edited:
Edgardo said:
P.S. By the way, what's your 3x3 average time?

Never really measured it, but I think maybe 1+ minutes. I'm more interested
in optimality (number of turns) and coming up with novel
operators (i.e. combinations of turns which do something interesting.)
 
I googled and found this pdf, "Mathematics of the Rubik's Cube":
http://web.usna.navy.mil/~wdj/papers/rubik.pdf
http://web.usna.navy.mil/~wdj/books.html

And some websites:
http://www.geocities.com/c_w_tsai/cube/
http://lar5.com/cube/

Methods with so-called commutators (I haven't tried them out myself but it seems popular among cubers):
http://grrroux.free.fr/begin/Begin.html
http://www.progsoc.uts.edu.au/~rheise/cube/
http://web.usna.navy.mil/~wdj/book/node179.html
http://www.geocities.com/jaapsch/puzzles/theory.htm

Check out the Fewest Move Challenge.
http://www.cubestation.co.uk/
http://games.groups.yahoo.com/group/fewestmoveschallenge/
 
Last edited by a moderator:

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