Search Results
Search type | Search syntax |
---|---|
Tags | [tag] |
Exact | "words here" |
Author |
user:1234 user:me (yours) |
Score |
score:3 (3+) score:0 (none) |
Answers |
answers:3 (3+) answers:0 (none) isaccepted:yes hasaccepted:no inquestion:1234 |
Views | views:250 |
Code | code:"if (foo != bar)" |
Sections |
title:apples body:"apples oranges" |
URL | url:"*.example.com" |
Saves | in:saves |
Status |
closed:yes duplicate:no migrated:no wiki:no |
Types |
is:question is:answer |
Exclude |
-[tag] -apples |
For more details on advanced search visit our help page |
A model category is a category equipped with notions of weak equivalences, fibrations and cofibrations allowing to run arguments similar to those of classical homotopy theory.
6
votes
Accepted
Homotopy pushout independent of factorization and symmetric in cofibration category
I don't remember how Baues does this exactly, but all facts of this sort follow from the Gluing Lemma (see Lemma 1.4.1 in this paper) and "Brown type factorization". By this I mean the following const …
3
votes
Accepted
Combinatorial proof that some model categories are monoidal/enriched?
This is far from a comprehensive answer, but since you ask for references, here are two.
The result for simplicial sets is obtained by an explicit computation in Appendix H of Joyal's The Theory of Q …
8
votes
Accepted
"Joyal type" model structure for (n,1)-categories?
I don't know if this will work with the definition of $(n, 1)$-categories exactly as stated by Lurie, but it will work with a reasonable modification.
Definition 2.3.4.1 from HTT basically says that …
9
votes
Accepted
Is there a model structure on (strict?) Monoidal Categories?
I'm not sure about the case of general monoidal categories. (Although I seem to recall a remark that there is no such structure since the category of monoidal categories is not cocomplete and a suitab …
2
votes
Ref request: making a homotopy equivalence fibrewise, in an abstract setting (eg fibration c...
I was quite sure that this was explicitly written down by Rădulescu-Banu or by Hirschhorn, but I cannot find this exact statement.
However, this follows directly by combining Theorems 7.5.10 and 7.6. …
4
votes
Accepted
Saturated classes and cofibrantly generated model structures
It doesn't make a difference as long as we restrict attention to compactly generated saturated classes, i.e. cofibrantly generated ones where generators can be chosen to have $\aleph_0$-small domains. …
2
votes
Cube Lemma on a cofibrantly generated (almost) model category
This is not an answer in a full generality, but it is certainly not the case if the domains of generating acyclic cofibrations are cofibrant. (I have a hard time thinking of an example of a model cate …
12
votes
Accepted
When do colimits agree with homotopy colimits?
I don't think we can expect to have one general answer to this question, only a collection of unrelated specialized results. Here are two more:
In the category of simplicial sets all filtered colimi …
10
votes
Accepted
Relative version of Quillen's theorem A
The condition that appears in the assumption of what you call "Relative Theorem A" was introduced by Grothendieck in Pursuing Stacks. It is a part of the definition of a basic localizer, i.e. a class …
5
votes
Accepted
How to simplify the proof of right-properness?
To complete the argument you need to apply K. Brown's Lemma. Call your model category $\mathcal{M}$, then the map $Z \to Y$ induces a pullback functor $\mathcal{M} \downarrow Y \to \mathcal{M} \downar …
6
votes
Accepted
recognising weak equivalences of simplicial sets
$\newcommand{\Ex}{\mathrm{Ex}}\newcommand{\Sd}{\mathrm{Sd}}$Consider the square
$$\begin{CD}
X @>{\sim}>> \Ex^\infty X \\
@V{f}VV @VV{\Ex^\infty f}V \\
Y @>>{\sim}> \Ex^\infty Y \textrm{.} \\
\end{CD …
7
votes
Accepted
Is the category of $G$-spaces a model category?
Yes, assuming that by "expected $G$-homotopy extension property" you mean the Serre $G$-cofibrations, not the Hurewicz $G$-cofibrations. A very explicit reference is Proposition A.1.18 in Schwede's Gl …
15
votes
Accepted
Constructing a "geometric" model structure on Cat by localizing the "categorical" model stru...
No, there are far too many "canonical cofibrations" for that. For example, let $A$ be a category with two objects and two parallel arrows between them. Then there is a unique functor $A \to [1]$ that …
3
votes
Morphisms every pushout of which is a weak equivalence
Here's a suggestion. Hopkins uses the name flat map for a morphism such that every pushout along it is a homotopy pushout. Rezk uses the name sharp map for the dual notion. (Roughly speaking, I think …
12
votes
Accepted
Is the localisation of a product of categories the product of the localisation?
It is true for arbitrary products of model categories (or just cofibration categories) as proven in Theorem 7.1.1 of http://arxiv.org/abs/math/0610009v4.
It is also true for finite products of arbitr …