Not signed in (Sign In)

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

  • Sign in using OpenID

Discussion Tag Cloud

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

Welcome to nForum
If you want to take part in these discussions either sign in now (if you have an account), apply for one now (if you don't).
    • CommentRowNumber1.
    • CommentAuthorJasonGross
    • CommentTimeNov 25th 2013
    What's the indexing category of the constant diagram functor used in http://ncatlab.org/nlab/show/Kan+extension#PointwiseByConicalLimits (that is, what is the domain category of Δ_{c'})? I suspect it's the terminal category, in which case I'm confused why the notation Δ_{c'} / p rather than just c' / p is being used. Either way, I think that part of the page needs a clarification (either replacing Δ_{c'} with c' and saying that it's a (co)slice category, or mentioning what the indexing category is for the constant diagram functor.)
    • CommentRowNumber2.
    • CommentAuthorZhen Lin
    • CommentTimeNov 25th 2013

    It’s not really a (co)slice category. As you surmised, the domain of Δ c\Delta_{c'} is indeed 𝟙\mathbb{1}, and the description as a comma category is completely accurate.

Add your comments
  • 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)