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• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeMar 2nd 2011
• (edited Mar 3rd 2011)

somebody asked the category theory mailing list what the word “encodes” is supposed to mean that appears a few times in the entry on sieves.

I guess I had written that a long time ago, and I think I had meant to amplify that while equivalent, the notion of sieve and the notion of subfunctor of a representable are different notions, even though one does determine or “encode” the other.

I should probably go through that whole entry and try to improve the exposition. But right now I don’t have the time.

• CommentRowNumber2.
• CommentAuthorFinnLawler
• CommentTimeMar 3rd 2011

I think the exposition at sieve is excellent, and doesn’t need significant improvement. So I’ve replaced the three uses of ’encode’ with ’present’, ’talk about’ and ’encapsulate’ respectively. I hope makes things clearer, or at least doesn’t obscure them.

Also, I added the abstract definition of a sieve as a fully faithful discrete fibration, which I think is cute.

• CommentRowNumber3.
• CommentAuthorUrs
• CommentTimeMar 3rd 2011
• (edited Mar 3rd 2011)

I think the exposition at sieve is excellent,

That’s in fact a relief. Believe it or not, I did not even dare to look at the entry again after I saw the message on the category theory mailing list. Because it was so long ago that I had written (parts of) it, I assumed it must have been all awkward and everyone would jump on me for how badly written it is, but I just did not (and do not) have the time and energy to look after it.

So many thanks indeed for taking care of it!

I wish there were some way that we could more widely spread the message that any questions and/or comments about $n$Lab entries should be posted to the $n$Forum.

• CommentRowNumber4.
• CommentAuthorzskoda
• CommentTimeMar 3rd 2011

I agree, this is one of the best $n$Lab entries.

• CommentRowNumber5.
• CommentAuthorUrs
• CommentTimeMar 3rd 2011

I have edited the sub-section layout a bit, trying to make it be better structured

• CommentRowNumber6.
• CommentAuthorUrs
• CommentTimeMar 3rd 2011

okay, good. I’ll post a brief reply to the cattheory mailing list then

• CommentRowNumber7.
• CommentAuthorFinnLawler
• CommentTimeMar 7th 2011

Urs said:

I wish there were some way that we could more widely spread the message that any questions and/or comments about nLab entries should be posted to the nForum.

I know what you mean -- I get the impression that there are lots of people who use the Lab (witness e.g. how often it's mentioned on MathOverflow) but don't contribute to discussion about it here. Maybe they don't know that the Forum is the place to discuss the Lab, or they do but are reluctant to contribute for some reason. There must be some way to make newcomers and potential contributors feel more welcome, but I don't know what it is.

On the other hand, I like the idea of having a certain amount of cross-over between the categories list and the nLab/nForum. There was some discussion about this a while ago, if I remember rightly, though I don't remember what conclusions were reached, if any.

• CommentRowNumber8.
• CommentAuthorUrs
• CommentTimeApr 29th 2013
• (edited Apr 29th 2013)

I have edited the very beginning of the Idea-section at sieve a little, in order to clarify the notion(s) of “sieve in a category” (as opposed to on an object).