[Haskell-cafe] permutations and performance

[Henning Thielemann]

John D. Ramsdell schrieb:
> Try deleting it and see what happens.

Erm, yes, this case is wrong:

 >>>>    | n <=  0 = []

There is _one_ permutation with no elements, namely [], thus it must be
         | n == 0 = [[]]