[Haskell-cafe] Deriving laws by systematic transformations

Armando Blancas abm221617 at gmail.com
Wed Aug 31 20:14:05 CEST 2011

Studying Wadler's "Comprehending Monads" and "Theorems for free!",
I've been unable to derive law (iv) and I'm not sure about (iii). Will
appreciate a pointer to similar examples or a massive hint. Here's my
attempt at (iii):

map f . unit x = map f [x]
                     = [f x]
                     = unit (f x)
                     = (unit . f) x
map f . unit = unit .f

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