[Haskell-cafe] Re: Why monoids will abide...

Andrzej Jaworski himself at poczta.nom.pl
Tue Jan 20 22:04:50 EST 2009

Monads are monoids in categories of functors C -> C 
Arrows are monoids in subcategories of bifunctors (C^op) x C -> C 
   Trees are a playing ground for functors in general:-)

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