Comments on: A meditation on semiadditive categories
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/
"A good stock of examples, as large as possible, is indispensable for a thorough understanding of any concept, and when I want to learn something new, I make it my first job to build one." - Paul HalmosFri, 06 Mar 2020 02:13:17 +0000
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By: Qiaochu Yuan
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/#comment-32576
Fri, 06 Mar 2020 02:13:17 +0000http://qchu.wordpress.com/?p=10590#comment-32576In reply to Beren Sanders.

Whoops, fixed, thanks!

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By: Beren Sanders
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/#comment-29998
Fri, 14 Feb 2020 06:23:23 +0000http://qchu.wordpress.com/?p=10590#comment-29998A slight correction: A “category with zero morphisms” is the same thing as a category enriched over pointed sets when the category of pointed sets is equipped with the smash product, not the cartesian product.
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By: Frank Murphy
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/#comment-9661
Tue, 18 Sep 2018 17:20:25 +0000http://qchu.wordpress.com/?p=10590#comment-9661Reblogged this on fmurphyrng.
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By: Coalgebras of distributions | Annoying Precision
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/#comment-6282
Sun, 20 Mar 2016 04:26:21 +0000http://qchu.wordpress.com/?p=10590#comment-6282[…] appearance of the diagonal map above can be put into a more abstract context. Recall that in any category with finite products, every object is canonically a cocommutative comonoid […]
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By: Tiny objects | Annoying Precision
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/#comment-5083
Thu, 07 May 2015 21:26:05 +0000http://qchu.wordpress.com/?p=10590#comment-5083[…] We saw in this blog post that zero objects are absolute for categories enriched over pointed sets, and finite coproducts / […]
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By: Projective objects | Annoying Precision
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/#comment-5035
Sun, 29 Mar 2015 01:11:19 +0000http://qchu.wordpress.com/?p=10590#comment-5035[…] a linear functor automatically preserves finite coproducts, is right exact iff it preserves […]
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By: Cartesian closed categories and the Lawvere fixed point theorem | Annoying Precision
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/#comment-3720
Sat, 28 Sep 2013 18:55:19 +0000http://qchu.wordpress.com/?p=10590#comment-3720[…] is the diagonal map; see, for example, this blog post. ( specializes to the paradoxical subset constructed in the usual proof of Cantor’s theorem.) […]
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By: The homotopy groups are only groups | Annoying Precision
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/#comment-3658
Sun, 08 Sep 2013 17:52:09 +0000http://qchu.wordpress.com/?p=10590#comment-3658[…] Example. If is an abelian group, then the group operation is itself a morphism in , giving a morphism from the Lawvere theory of abelian groups to . Hence naturally acquires the structure of an abelian group. (We discussed a more general setting in which such an abelian group structure exists in this previous post on semiadditive categories.) […]
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By: Monomorphisms and epimorphisms « Annoying Precision
https://qchu.wordpress.com/2012/09/14/a-meditation-on-semiadditive-categories/#comment-2229
Sun, 30 Sep 2012 00:42:20 +0000http://qchu.wordpress.com/?p=10590#comment-2229[…] Previously we discussed categories with finite biproducts, or semiadditive categories. Today, partially as a further warmup for the axioms defining an abelian category, we’ll discuss monomorphisms and epimorphisms. […]
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