From: David Roberts <david.roberts@adelaide.edu.au>
To: "categories@mta.ca" <categories@mta.ca>
Subject: (In)accessible comonads and (non)Grothendieck toposes
Date: Thu, 9 May 2013 03:07:21 +0000 [thread overview]
Message-ID: <E1UayTa-0007AW-JX@mlist.mta.ca> (raw)
Hi all,
I am just wondering where it was first stated (for both directions) that the category of coalgebras for a comonad on a Grothendieck topos E is again Grothendieck if and only if the underlying endofunctor of E is accessible.
A modern argument might go as: the topos of coalgebras is Grothendieck if and only if it is locally presentable if and only if the endofunctor is accessible, the original probably just mentioned preservation of filtered colimits.
Many thanks,
David Roberts
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next reply other threads:[~2013-05-09 3:07 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-05-09 3:07 David Roberts [this message]
2013-05-11 15:26 ` Prof. Peter Johnstone
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