[Haskell-cafe] When is a composition of catamorphisms a catamorphism?
wren ng thornton
wren at freegeek.org
Tue Aug 28 05:35:17 CEST 2012
On 8/26/12 9:10 PM, Sebastien Zany wrote:
> Thanks Wren. That was my guess too, but it seems not necessary:
Well, sure. I was meaning in the general case. If you have the right
kind of distributivity property (as colah suggests) then things will
work out for the particular case. But, having the right kind of
distributivity property typically amounts to being a natural
transformation in some appropriately related category; so that just
defers the question to whether an appropriately related category always
exists, and whether we can formalize what "appropriately related" means.
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