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.

• CommentRowNumber1.
• CommentAuthorUrs
• CommentTimeJun 23rd 2016

I have added the characterization of Quillen equivalences in the case that the right adjoint creates weak equivalences, here.

• CommentRowNumber2.
• CommentAuthorDmitri Pavlov
• CommentTimeApr 6th 2020

Added redirects.

• CommentRowNumber3.
• CommentAuthorHurkyl
• CommentTimeJan 13th 2021

Added the change-of-base Quillen equivalence between over-categories for suitable weak equivalences between the bases.

• CommentRowNumber4.
• CommentAuthorTim_Porter
• CommentTimeJun 17th 2021
• (edited Jun 17th 2021)

The two categories C and D had got mixed up at one place, so $\eta_d:d\to R(L(d))$ was there instead of $\eta_c:c\to R(L(c))$. I think it is right now. (I checked in the reference given and they seem to have the mistake as well. Confusing.)

In fact this part (proposition 2.3) of the entry seems to be in bit of a mess, as $R$ and $L$ or $C$ and $D$ have somehow ended up being swapped from earlier on in the entry. I am confused!!!

• CommentRowNumber5.
• CommentAuthorHurkyl
• CommentTimeAug 20th 2021

The given sufficient condition for $C/S \leftrightarrows C/T$ to be a Quillen equivalence is actually a necessary condition too.

• CommentRowNumber6.
• CommentAuthorUrs
• CommentTimeAug 20th 2021
• (edited Aug 20th 2021)

Then let’s make this part of the statement, not hide it in the proof.

I have reworked both the statement and the proof a fair bit (here), adding more explanation throughout (the key use of 2-out-of-3 wasn’t even mentioned before).

Also I cross-linked with base change Quillen adjunction. The whole proposition would rather be found there than here, and so I am copying it over now.

1. Fixed typo in Proposition 2.3

Anonymous

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)