TY - CPAPER KW - free theorems KW - Haskell KW - monads KW - non-determinism KW - permutation KW - sorting AU - Jan Christiansen AU - Nikita Danilenko AU - Sandra Dylus BT - Proceedings of the 21st ACM SIGPLAN International Conference on Functional Programming DO - 10.1145/2951913.2951949 PB - ACM PY - 2016 SN - 978-1-4503-4219-3 SP - 168 EP - 179 T2 - Proceedings of the 21st ACM SIGPLAN International Conference on Functional Programming TI - All Sorts of Permutations (Functional Pearl) ER -