On: The perplexing life of Ernő Rubik (1986)

[passivepinetree]

That's super interesting. Do you have a source?

[schmich → passivepinetree]

God's number is 20: http://www.cube20.org/

They pruned a bunch and then did brute force evaluation of the remaining "hard" positions. It seems strange that there hasn't been a more elegant approach to proving this. An interesting (if obvious) corollary to this result is that the maximum moves between any two Rubik's configurations is 20.

The relevant HN thread at that time: https://news.ycombinator.com/item?id=1587340

[rurban → schmich]

In combinatorics counting is always the best strategy. People are usually not good in counting, computers are better fit. So no surprise.

[passivepinetree → schmich]

You're the best. Thank you!

[TrunkleBob → passivepinetree]

The page from the team that completed the proof: http://www.cube20.org/

[DSMan195276 → passivepinetree]

http://www.cube20.org/