[Haskell-beginners] Category question

[Ertugrul Söylemez]

Manfred Lotz <manfred.lotz at arcor.de> wrote:

> My question: Because I cannot think of any counterexample for the last
> statement I would like to know if I just could omit this from the
> definition and formulate this as a small theorem.
>
> Or does there exist a counterexample where all conditions of a
> category hold but there exist two objects A, and B where we have idB
> . f <> f and/or f .idA <> f?

The successor function is a morphism from the set of natural numbers to
itself.  This is the "and" case of the "and/or".


Greets,
Ertugrul

-- 
nightmare = unsafePerformIO (getWrongWife >>= sex)
http://ertes.de/
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 836 bytes
Desc: not available
URL: <http://www.haskell.org/pipermail/beginners/attachments/20120528/e4fcaf09/attachment.pgp>