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Mar
29
comment Category theory coproduct beginner question
User87690 if you consider OP question worthy of your (precious?) time to the extent that you answer it, why don't you upvote the question? Also considering that this is the OP's first question here.
Mar
29
comment Motivation behind the definition of equivalence of categories.
Your textbook has to resort to "equality of isomorphism classes of functors" to justify equivalence of categories to a beginner? Wow! Good luck with the rest of the book. If your purpose is to study category theory, I suggest you get a proper introductory textbook on CT. Awodey, or "the joy of cats" (free online) come to mind. MacLane's CWM is also excellent of course.
Mar
23
comment The monoid of integers is not free
@Craig If you like and accept this answer, why don't you upvote it?
Mar
23
comment The monoid of integers is not free
@Craig Yes you should definitely get your CT knowledge from a good textbook. The "Joy of cats" is excellent and freely available online. Yesterday I found : math.jhu.edu/~eriehl/context.pdf which seems well done.
Jan
26
comment Definition of the Diagonal functor
Thank you @JeremyRickard and Najib for the enlightening discussion
Jan
13
comment What is the geometric meaning of representability?
Is there an accepted or acceptable name for the functor in your last example?
Jan
10
comment codiagonal functor and faithfullness
@GiorgioMossa very good explanation and notation. I suggest you do not erase or modify what you have written. Perhaps you might add some type theory notation for those more familiar with it.
Oct
6
comment Analogy between the notion of adjunction of two functors, and the notion of factorization of a morphism.
What is Fix(...) ?
Aug
6
comment homology group of adjunction space
Thank you rmznyzgyr
Aug
5
comment homology group of adjunction space
could you please indicate where does this text come from?
Jul
30
comment Prove that a morphism $\alpha$ of $Fun(\mathcal{A},\mathcal{B})$ is an isomorphism iff each component $\alpha_A$, is an isomorphism in $\mathcal{B}$
what is a computational engineer?
Jul
10
comment Grothendieck's yoga of six operations - in relatively basic terms?
Thank you Roland
Jul
8
comment Grothendieck's yoga of six operations - in relatively basic terms?
Where are you reading this from?
Jul
8
comment Grothendieck's yoga of six operations - in relatively basic terms?
Could you please give a reference source to all this?
Jul
1
comment Group action on a category
@ZhenLin where can I read about "pseudo G-action on a category C"?
Jun
24
comment Monoid as a single object category
Nice notes Peter. And nice blog too. I will contact you there.
Jun
24
comment Essentially surjective property is closed under composition of functors.
@AlexG. In a context, like this one at M.SE, where you are teaching/explaining something, it is better to be unambiguous since the OP is probably less experienced than yourself with a specific subject matter
Jun
11
comment Uniqueness of Exponential Objects up to Isomorphism in any Category
To distinguish it from Awodey's little book (first edition only had 256 pages)
May
31
comment Intersecting Scopes: Quantifier and Predicate
@user3578468 this is simply a miswritten expression. Perhaps a typo. That's all.
May
24
comment Equivalence between category of $R$-modules and $S$-modules
what is $M_n(A)$?