[Haskell-cafe] Design Patterns by Gamma or equivalent
Colin Paul Adams
colin at colina.demon.co.uk
Tue Mar 17 05:54:59 EDT 2009
>>>>> "Wolfgang" == Wolfgang Jeltsch <g9ks157k at acme.softbase.org> writes:
Wolfgang> By the way, the documentation of Control.Category says
Wolfgang> that a category is a monoid (as far as I remember). This
Wolfgang> is wrong. Category laws correspond to monoid laws but
Wolfgang> monoid composition is total while category composition
Wolfgang> has the restriction that the domain of the first
Wolfgang> argument must match the codomain of the second.
I'm reading the Barr/Wells slides at the moment, and they say the
"Thus a category can be regarded as a generalized monoid, or a
'monoid with many objects'"
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