Skip to main content
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
Results tagged with
Search options not deleted user 14969

Enriched categories, topoi, abelian categories, monoidal categories, homological algebra.

61 votes
8 answers
7k views

Natural transformations as categorical homotopies

Every text book I've ever read about Category Theory gives the definition of natural transformation as a collection of morphisms which make the well known diagrams commute. There is another possible d …
Giorgio Mossa's user avatar
41 votes

Is Mac Lane still the best place to learn category theory?

I doubt that someone could learn higher category theory (and more in general higher dimensional algebra) without first studying a little of category theory, mostly because the definition given in such …
21 votes
3 answers
3k views

Relation between monads, operads and algebraic theories

I've begun to interest in algebraic theories and their categorical models: in particular monads, generalized multicategories and operads, lawvere theories and their generalization. Is there any refere …
Giorgio Mossa's user avatar
20 votes
5 answers
3k views

Computations in $\infty$-categories

Direct to the point. Since now I've looked a lot of presentations of $\infty$-categories, but it seems that the only way to do explicit computations on these objects is via model categories. Is that s …
Giorgio Mossa's user avatar
13 votes
Accepted

Categories presented with Arrows only, no objects: partial monoids

Of course you can define a (just-arrow) category $\mathcal C$ like a partial algebra which consist of: a set $\mathcal C$ (namely the set of arrows of your category), a set $D_\mathcal{C} \subseteq \ …
Giorgio Mossa's user avatar
9 votes

Why did Voevodsky consider categories "posets in the next dimension", and groupoids the corr...

I cannot say what exactly Voevodsky meant but here is a wild guess. Disclaimer in what follows I use heavily type theoretic notation, so you have trouble understanding feel free to ask in the comment …
Giorgio Mossa's user avatar
8 votes
3 answers
3k views

What is higher dimensional algebra?

Could anyone explain what higher dimensional algebra is? I tried to look on the web but I couldn't find a satisfactory definition, the ones that I found are too vague. What I'm looking for is a good …
Giorgio Mossa's user avatar
7 votes

Multicategories vs Categories

Is there a way to recapture the additional understanding imparted by multicategories using higher categories? Well I would say so. Multicategories are basically categories whose morphisms have multi …
Giorgio Mossa's user avatar
6 votes

Category theorists stance on deductive systems

I think the idea should pretty much like this: once you drop the requirement for the deductive system to be freely generated from the axioms by the inference rules (i.e. you accept the existence of no …
Giorgio Mossa's user avatar
6 votes
3 answers
2k views

Monad arising from operad

It's known that from every operad arises a cartesian monad whose algebras are the algebras for the operad. Leinster proved that there are different operads from which arise the same monad, in this way …
Giorgio Mossa's user avatar
5 votes

What is the difference between a function and a morphism?

Another interesting reason why categories cannot be identified always with categories having functions for morphisms is given in this paper, by Peter Freyd in which is proven that there are some categ …
Giorgio Mossa's user avatar
5 votes
Accepted

Motivation/intuition behind the definition of delta-functors and related concepts

I am not an expert on the subject but looking at the definition I would dare to say that these are basically the axioms that characterize an homology theory, if it weren't for the fact the $\delta$ ma …
Giorgio Mossa's user avatar
4 votes

Natural transformations as categorical homotopies

Following the previous indication of Professor Brown I want to add another possible way to see natural transformation which is a generalization of the previous definition. Given categories $\mathc …
Giorgio Mossa's user avatar
4 votes

The symmetric monoidal closed structure on the category of $\mathcal{F}$-cocomplete categori...

I am not aware of Kock's works. Nevertheless Kelly provides the definition of its tensor product in the next page: it defines its tensor product $\mathcal A \otimes_{\mathcal F} \mathcal B$ as the $\ …
Giorgio Mossa's user avatar
4 votes
2 answers
646 views

Equivalence in $\infty$-categories

In every $n$-category (weak or strict) can be defined the concept of equivalence via a recursive definition: * an equivalence in a set ($0$-category) is just an identity; * for each $n \in \mathbb N$ …
Giorgio Mossa's user avatar

15 30 50 per page