[Haskell-cafe] Article review: Category Theory

Brian Hulley brianh at metamilk.com
Wed Jan 17 16:11:13 EST 2007

Yitzchak Gale wrote:
> David House wrote:
>> I've added a bit more explanation, so it may now be palatable. It is
>> quite a hard exercise, though, perhaps it shouldn't come so early on.
> In my opinion, it is now much more clear. And it is a very
> instructive example.
> If people still find it too hard, you could add the additional
> hint: Keep in mind that there are no morphisms
> other than the ones shown in the diagram.

Ok I understand it now, because David has just clarified offlist the thing 
that puzzled me about the diagram: namely that morphisms have an 
individuality of their own that isn't fully determined by the lhs and rhs of 
the arrow like the relationship between a function and its type.


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