User Geoff

8 votes

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Is taking (co)limits exact in an Abelian category?

answered Jul 8, 2022 at 17:44

6 votes

Why the name "category"?

answered Feb 18 at 20:53

5 votes

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All $9$-dimensional semisimple $\mathbb{R}$-algebras up to isomorphism

answered Jan 5, 2017 at 9:51

4 votes

Do adjoint functors "preserve" commutative diagrams?

answered Feb 5, 2017 at 20:15

4 votes

nonequivalence of category of Groups and category of Pointed Groups

answered Jun 18, 2016 at 23:01

4 votes

Why $\mathbb{Z}_{p}[p^{1/p^{\infty}}]/p$ $\cong$ $\mathbb{F}_{p}[t^{1/p^{\infty}}]/t$?

answered Jun 2, 2021 at 14:47

3 votes

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Reference request: Galois categories

answered Jan 22, 2022 at 22:22

3 votes

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Duality of diagrams for fibration and cofibration

answered May 6, 2016 at 6:45

2 votes

generator is an ideal of a polynomial ring

answered May 11, 2016 at 3:07

2 votes

For all $\xi \in \mathbb{C}$ we have $e^{-\pi\xi^2}=\int_{-\infty}^\infty \! e^{-\pi x^2}e^{2\pi ix\xi}\ \mathrm{d}x.$

answered Jan 5, 2017 at 4:22

2 votes

What exactly are the meaning of the followings in the definition of a category?

answered Jun 26, 2016 at 3:32

2 votes

Zariski topology and product topology on $\mathbb A_k^m \times \mathbb A_k^n$

answered Aug 23, 2018 at 2:59

2 votes

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Simple examples of non-representable functors

answered May 11, 2019 at 15:41

2 votes

Order of elements of the group of $3 \times 3$ upper-triangular matrices over $\mathbb{Z}/p\mathbb{Z}$ with $1$'s in the diagonal

answered Mar 3, 2021 at 22:20

2 votes

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Spec of $\mathfrak{p}$-adic completion of number ring

answered Apr 10, 2021 at 20:06

2 votes

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Semi-simple product of $p$-adic numbers

answered Jul 8, 2022 at 18:18

2 votes

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Is there a finite non-regular ring which is a direct product of local rings with atleast one not a field?

answered Aug 5, 2022 at 15:19

2 votes

A question on nomenclature of Image and Coimages in categories with zero-morphisms.

answered Sep 20, 2021 at 10:58

2 votes

What is the difference between a presheaf and a contravariant Hom functor

answered Aug 1 at 15:46

1 vote

A Sub-group of affine group

answered May 18 at 15:00

1 vote

Accepted

Definition of strict 2-monad on Cat

answered Sep 21, 2021 at 12:16

1 vote

Accepted

About convolution, how to finish the proof

answered Jul 7, 2021 at 4:55

1 vote

(Co)Homology of topoi

answered Feb 4, 2022 at 23:54

1 vote

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Intersection of all maximal ideal in a semi-simple ring.

answered Apr 12, 2021 at 15:54

1 vote

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Subobject classifier of $C$ is the same as the terminal object of $D$

answered May 5, 2021 at 21:49

1 vote

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Show that, given $f:M→N$, if M is an artinian module so is N

answered Apr 6, 2021 at 23:23

1 vote

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$H_{n}:Comp(\mathcal{C}) \to \mathcal{C}$ is an additive functor implies $H_{n}:K(\mathcal{C}) \to \mathcal{C}$ is an additive functor.

answered Jan 29, 2021 at 18:37

1 vote

Definition of a limit when there are no cones?

answered Jan 28, 2021 at 18:35

1 vote

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what are the arrows in between the objects $M \otimes_U N$ in the category $\mathscr{M} \otimes_U N$?

answered Feb 2, 2021 at 21:57

1 vote

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Submodules of a $\mathbb{C}[x]$-module

answered Feb 7, 2021 at 1:20

Stack Exchange Network

49 Answers

Is taking (co)limits exact in an Abelian category?

Why the name "category"?

All $9$-dimensional semisimple $\mathbb{R}$-algebras up to isomorphism

Do adjoint functors "preserve" commutative diagrams?

nonequivalence of category of Groups and category of Pointed Groups

Why $\mathbb{Z}_{p}[p^{1/p^{\infty}}]/p$ $\cong$ $\mathbb{F}_{p}[t^{1/p^{\infty}}]/t$?

Reference request: Galois categories

Duality of diagrams for fibration and cofibration

generator is an ideal of a polynomial ring

For all $\xi \in \mathbb{C}$ we have $e^{-\pi\xi^2}=\int_{-\infty}^\infty \! e^{-\pi x^2}e^{2\pi ix\xi}\ \mathrm{d}x.$

What exactly are the meaning of the followings in the definition of a category?

Zariski topology and product topology on $\mathbb A_k^m \times \mathbb A_k^n$

Simple examples of non-representable functors

Order of elements of the group of $3 \times 3$ upper-triangular matrices over $\mathbb{Z}/p\mathbb{Z}$ with $1$'s in the diagonal

Spec of $\mathfrak{p}$-adic completion of number ring

Semi-simple product of $p$-adic numbers

Is there a finite non-regular ring which is a direct product of local rings with atleast one not a field?

A question on nomenclature of Image and Coimages in categories with zero-morphisms.

What is the difference between a presheaf and a contravariant Hom functor

A Sub-group of affine group

Definition of strict 2-monad on Cat

About convolution, how to finish the proof

(Co)Homology of topoi

Intersection of all maximal ideal in a semi-simple ring.

Subobject classifier of $C$ is the same as the terminal object of $D$

Show that, given $f:M→N$, if M is an artinian module so is N

$H_{n}:Comp(\mathcal{C}) \to \mathcal{C}$ is an additive functor implies $H_{n}:K(\mathcal{C}) \to \mathcal{C}$ is an additive functor.

Definition of a limit when there are no cones?

what are the arrows in between the objects $M \otimes_U N$ in the category $\mathscr{M} \otimes_U N$?

Submodules of a $\mathbb{C}[x]$-module