[Haskell-cafe] Re: howto tuple fold to do n-ary cross product?

Martijn van Steenbergen martijn at van.steenbergen.nl
Sun Nov 30 17:13:03 EST 2008

Luke Palmer wrote:
> The other nice one problem is allowing the argument itself to be
> infinite (you have to require all of the lists to be nonempty).

I think the requirement has to be a lot stronger for that to work.

If every sublist has two elements, the answer is 2^infinity lists which 
is uncountable.

In order for the answer to be countable, you have to require that only a 
finite number of sublists contain more than one element, at which point 
you can use your omega monad again.


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