# Start a new discussion

## Not signed in

Want to take part in these discussions? Sign in if you have an account, or apply for one below

## Site Tag Cloud

Vanilla 1.1.10 is a product of Lussumo. More Information: Documentation, Community Support.

• CommentRowNumber1.
• CommentAuthorMike Shulman
• CommentTimeDec 12th 2011

I figured it was high time we had a general page on truncated objects. I think some number of links, and perhaps redirects, which currently point to n-truncated object of an (infinity,1)-category would more usefully point here, but I haven’t updated any yet.

• CommentRowNumber2.
• CommentAuthorTobyBartels
• CommentTimeDec 12th 2011
• (edited Dec 13th 2011)

Not only a number of links and redirects, but the redirect created by your link in this very forum discussion! I was going to clear it, but then I figured that I’d move more redirects, and then I realised that I have absolutely no idea what the difference is supposed to be between these two pages. Isn’t a truncated object necessarily an n-truncated object of an (infinity,1)-category for some $n$ and some $(\infty,1)$-category?

• CommentRowNumber3.
• CommentAuthorMike Shulman
• CommentTimeDec 13th 2011

Isn’t a truncated object necessarily an n-truncated object of an (infinity,1)-category for some n and some (∞,1)-category?

Well, interpreting that statement literally, it is true, but it’s not true that for a given $n$-category $C$ the notion of $k$-truncated object in $C$ coincides with the notion of $m$-truncated object in any $(\infty,1)$-category. If $k$ is of the form $(k,0)$ then it is true – we can take the underlying $(n,1)$-category of $C$ and regard it as an $(\infty,1)$-category. But the underlying $(2,1)$-category of a 2-category doesn’t see the difference between 1-truncated and (1,0)-truncated objects.

Personally, I would suggest we link to n-truncated object of an (infinity,1)-category when the reference is specifically to $(\infty,1)$-categories, and to truncated object if not.

• CommentRowNumber4.
• CommentAuthorTobyBartels
• CommentTimeDec 13th 2011

Ah, I see now! Your article is about $(\infty,\infty)$-categories, while Urs’s is about $(\infty,1)$-categories (although maybe it’s unfair to ascribe the articles to people in this way). As your topic is more general, most redirects should go to your article by default, even if links might go to Urs’s. I have done this.

• Please log in or leave your comment as a "guest post". If commenting as a "guest", please include your name in the message as a courtesy. Note: only certain categories allow guest posts.
• To produce a hyperlink to an nLab entry, simply put double square brackets around its name, e.g. [[category]]. To use (La)TeX mathematics in your post, make sure Markdown+Itex is selected below and put your mathematics between dollar signs as usual. Only a subset of the usual TeX math commands are accepted: see here for a list.

• (Help)