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Aug 19, 2017 at 15:56 answer added Tim Campion timeline score: 1
Aug 16, 2017 at 23:58 comment added Tim Campion I just found a preprint of Boyarchenko and Drinfeld which studies "well-idempotent" and "co-well-idempotent" objects. Their terminology is "closed idempotent" and "open idempotent".
Aug 10, 2017 at 16:24 comment added Mike Shulman You're very polite, but of course my "answer" was not really an answer to the question as you asked it. It's intriguing that while the answer to question 1 is "no" in both symmetric and non-symmetric contexts, the answer to question 2 is "yes" in the symmetric context but "no" in the non-symmetric one. I wonder what the answer to question 3 is in the non-symmetric context.
Aug 9, 2017 at 16:15 comment added Tim Campion I've accepted MTyson's answer, although of course the complete answer to my question also involves Anton Fetisov's answer, or Will Sawin's simplification. Mike Shulman's answer also provides important context!
Aug 9, 2017 at 16:14 vote accept Tim Campion
Aug 9, 2017 at 12:16 answer added Will Sawin timeline score: 3
Aug 9, 2017 at 0:47 comment added Tim Campion Following Anton's example below, note that if $C$ is a self-dual category (i.e. equivalent to its opposite), then $C^\mathbb{N}$ is self-dual and idempotent in $Dist$, but it is typically not well-idempotent, -- e.g. if $C$ is finite sets and bijections. So this whole business was not as sharp as I thought it was -- well-idempotency is stronger than idempotency + self-duality. I'm not sure what the "right" notion of "self dual idempotent object" is, but being well-idempotent might be a reasonable guess. Perhaps there's additional coherences to be had, though.
Aug 9, 2017 at 0:39 history edited Tim Campion CC BY-SA 3.0
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Aug 9, 2017 at 0:28 answer added Anton Fetisov timeline score: 4
Aug 8, 2017 at 21:07 vote accept Tim Campion
Aug 8, 2017 at 21:10
Aug 7, 2017 at 23:09 answer added MTyson timeline score: 6
Aug 7, 2017 at 10:24 answer added Mike Shulman timeline score: 12
Aug 4, 2017 at 21:32 history edited Tim Campion CC BY-SA 3.0
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Aug 4, 2017 at 21:27 history asked Tim Campion CC BY-SA 3.0