Google even and odd permutations to learn more :)
What a lovely independent discovery! The context is similar to the (un)solvability of the 15 puzzle.
https://en.wikipedia.org/wiki/15_puzzle#Solvability
Ahhh fascinating! :) Thank you for the pointer.
alt Hacker News
What a lovely independent discovery! The context is similar to the (un)solvability of the 15 puzzle.
https://en.wikipedia.org/wiki/15_puzzle#Solvability