User fosco

25 votes

"Advice to young mathematicians"

answered Aug 22, 2017 at 8:12

12 votes

Understanding the Beck-Chevalley condition

answered Mar 24, 2017 at 12:15

12 votes

Is Top provably not cartesian closed?

answered Nov 10, 2012 at 10:37

11 votes

Accepted

Theorems implied by Yoneda's lemma?

answered Jan 30, 2014 at 0:19

11 votes

What is the Jacobian matrix?

answered Dec 21, 2010 at 19:31

11 votes

Accepted

On a topological proof of the infinitude of prime numbers.

answered Dec 20, 2011 at 19:19

10 votes

Accepted

Adjoint functors preserve (co)products

answered Jun 23, 2011 at 8:05

8 votes

What should be the next step in studying category theory?

answered Dec 27, 2011 at 13:40

7 votes

Accepted

Every Presheaf Is Colimit of Representables

answered Feb 22, 2014 at 18:50

7 votes

Have there been efforts to introduce non Greek or Latin alphabets into mathematics?

answered Dec 27, 2016 at 22:03

7 votes

Ordinals in category theory?

answered Jul 25, 2018 at 22:58

6 votes

Accepted

How to think about the octohedral axiom for triangulated categories?

answered Jun 19, 2018 at 11:18

6 votes

Why an integral symbol for the category of elements of a presheaf?

answered Feb 10, 2014 at 19:46

6 votes

Integrals in analysis and category theory

answered May 9, 2014 at 9:52

6 votes

Categories which are dually equivalent to themselves.

answered Aug 10, 2016 at 11:08

6 votes

Accepted

Commutativity of categorical limits

answered Jun 26, 2022 at 11:18

5 votes

Accepted

Does $A \times B \cong A \times C$ imply $B \cong C$ in arbitrary category?

answered Oct 25, 2021 at 9:26

5 votes

Accepted

Familiar categorical limits viewed elegantly as weighted limits?

answered Aug 10, 2016 at 10:06

5 votes

Proof that $B^{A \times A'}$ is isomorphic to $(B^A)^{A'}$ in a CCC

answered Jan 30, 2013 at 8:31

5 votes

Grothendieck's yoga of six operations - in relatively basic terms?

answered Jan 4, 2017 at 20:52

5 votes

Accepted

Why is adjoining a unit the algebraic counterpart to the one point compactification?

answered Jan 5, 2017 at 12:45

5 votes

Accepted

Using the Yoneda Lemma to construct a left adjoint to the restriction functor $U : C^A \to C^{\operatorname{ob} A}$

answered Jan 6, 2020 at 22:17

5 votes

Accepted

Why are (co-)ends called "(co-)ends"?

answered Sep 15, 2020 at 16:32

4 votes

Accepted

Problem book on functors and category theory?

answered Nov 25, 2020 at 10:50

4 votes

Accepted

Are extensions of simplicial objects to functors $\mathsf{sSet} \to \mathsf{C}$ Kan extensions?

answered Aug 30, 2020 at 13:10

4 votes

Accepted

Definition of representable functor with values in $Ab$

answered Feb 12, 2021 at 16:17

4 votes

Can two morphisms with equal mappings be distinct in category theory?

answered Mar 1, 2020 at 15:46

4 votes

Accepted

${\rm Hom}(\textbf{G},\textbf{Ab})$ is the category of $G$-modules

answered Mar 23, 2020 at 14:43

4 votes

Category theory results

answered Dec 24, 2019 at 10:10

4 votes

If $F$ and $G$ are biadjoint, how is $\operatorname{Nat}(F,F)\simeq\operatorname{Nat}(G\circ F,1)$?

answered Sep 20, 2017 at 8:06

Stack Exchange Network

191 Answers

"Advice to young mathematicians"

Understanding the Beck-Chevalley condition

Is Top provably not cartesian closed?

Theorems implied by Yoneda's lemma?

What is the Jacobian matrix?

On a topological proof of the infinitude of prime numbers.

Adjoint functors preserve (co)products

What should be the next step in studying category theory?

Every Presheaf Is Colimit of Representables

Have there been efforts to introduce non Greek or Latin alphabets into mathematics?

Ordinals in category theory?

How to think about the octohedral axiom for triangulated categories?

Why an integral symbol for the category of elements of a presheaf?

Integrals in analysis and category theory

Categories which are dually equivalent to themselves.

Commutativity of categorical limits

Does $A \times B \cong A \times C$ imply $B \cong C$ in arbitrary category?

Familiar categorical limits viewed elegantly as weighted limits?

Proof that $B^{A \times A'}$ is isomorphic to $(B^A)^{A'}$ in a CCC

Grothendieck's yoga of six operations - in relatively basic terms?

Why is adjoining a unit the algebraic counterpart to the one point compactification?

Using the Yoneda Lemma to construct a left adjoint to the restriction functor $U : C^A \to C^{\operatorname{ob} A}$

Why are (co-)ends called "(co-)ends"?

Problem book on functors and category theory?

Are extensions of simplicial objects to functors $\mathsf{sSet} \to \mathsf{C}$ Kan extensions?

Definition of representable functor with values in $Ab$

Can two morphisms with equal mappings be distinct in category theory?

${\rm Hom}(\textbf{G},\textbf{Ab})$ is the category of $G$-modules

Category theory results

If $F$ and $G$ are biadjoint, how is $\operatorname{Nat}(F,F)\simeq\operatorname{Nat}(G\circ F,1)$?