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7 votes

Some questions about Enrichement Definition in Category Theory

answered Sep 17, 2018 at 17:15

7 votes

Why use $\infty$-categories over model categories?

answered Jun 13, 2022 at 0:09

6 votes

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Non abelian group with 27 elements and its center

answered May 23, 2018 at 17:28

6 votes

$f:S^1\rightarrow S^1$ injective but not surjective

answered Jun 13, 2017 at 11:17

6 votes

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What is a regular submanifold?

answered Nov 24, 2017 at 17:14

6 votes

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Why are bilinear maps represented as members of the tensor space $V^\otimes V^$ opposed to just members of the tensor space $V\otimes V$?

answered Feb 4, 2018 at 21:53

5 votes

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A linear operator $P: V \to V$ is a projection operator if and only if $P^2 =P$.

answered Sep 13, 2016 at 6:00

5 votes

Skeletons of small categories and the axiom of choice.

answered May 18, 2018 at 23:15

4 votes

Quotient group $G/H$ is abelian iff $[G,G] \subseteq H$

answered Dec 12, 2018 at 18:17

4 votes

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Why is the open subscheme $D(p)\cup D(T)$ in $\text{Spec } \mathbb Z[T]$ not affine?

answered May 22, 2019 at 16:11

4 votes

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Continuous function $f$ differentiable implies that $f'$ is also differentiable

answered Mar 14, 2016 at 20:02

4 votes

"This statement is false."

answered Mar 14, 2016 at 21:10

4 votes

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What is a bounded quantifier?

answered Mar 31, 2016 at 1:04

4 votes

Why is $ \{(1/2)^n : n \in \mathbb{N} \} \cup \{ 0 \} $ not compact?

answered Apr 20, 2016 at 22:45

4 votes

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Why can't you count up to aleph null?

answered Apr 28, 2016 at 1:44

4 votes

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Group of order $2555$ is cyclic

answered Sep 28, 2017 at 5:20

4 votes

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What is the "Unit Element" in a Categorical Monad?

answered Sep 29, 2017 at 23:48

3 votes

why need initial object and pushout to have coproduct. why not pushout by itself

answered Dec 24, 2017 at 4:28

3 votes

Super simple question about an example of the module of differentials of a polynomial ring

answered Jan 3, 2018 at 8:52

3 votes

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Example of a subgroup (of a ring's additive group) that is not an ideal?

answered Jan 5, 2018 at 21:23

3 votes

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Let $M=\mathbb{Z} \oplus \mathbb{Z}/4\mathbb{Z}$ as a $\mathbb{Z}$-module. Is M free?

answered May 16, 2017 at 22:58

3 votes

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Checking of Subspace

answered Jun 3, 2017 at 4:16

3 votes

No nontrivial subspaces implies irreducibility of characteristic polynomial

answered Jan 17, 2019 at 5:11

3 votes

Lifting of principal G-bundles

answered Oct 25, 2021 at 5:05

3 votes

The definition of finite group scheme.

answered Mar 30, 2018 at 23:02

3 votes

What is $k[x,y]_{(x,y)}$?

answered Nov 6, 2021 at 3:39

3 votes

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Why is Vakil's definition of "distinguished affine base" of a scheme not a base in the usual sense?

answered Nov 13, 2021 at 2:35

3 votes

Does being isomorphic to a full subcategory imply being isomorphic to the catgeory

answered Sep 16, 2022 at 20:28

2 votes

Relation between a universal cover, a fibre, and the fundamental group

answered Apr 15, 2018 at 21:53

2 votes

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Order element of a quotient group

answered Apr 23, 2018 at 17:25

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113 Answers

Some questions about Enrichement Definition in Category Theory

Why use $\infty$-categories over model categories?

Non abelian group with 27 elements and its center

$f:S^1\rightarrow S^1$ injective but not surjective

What is a regular submanifold?

Why are bilinear maps represented as members of the tensor space $V^\otimes V^$ opposed to just members of the tensor space $V\otimes V$?

A linear operator $P: V \to V$ is a projection operator if and only if $P^2 =P$.

Skeletons of small categories and the axiom of choice.

Quotient group $G/H$ is abelian iff $[G,G] \subseteq H$

Why is the open subscheme $D(p)\cup D(T)$ in $\text{Spec } \mathbb Z[T]$ not affine?

Continuous function $f$ differentiable implies that $f'$ is also differentiable

"This statement is false."

What is a bounded quantifier?

Why is $ \{(1/2)^n : n \in \mathbb{N} \} \cup \{ 0 \} $ not compact?

Why can't you count up to aleph null?

Group of order $2555$ is cyclic

What is the "Unit Element" in a Categorical Monad?

why need initial object and pushout to have coproduct. why not pushout by itself

Super simple question about an example of the module of differentials of a polynomial ring

Example of a subgroup (of a ring's additive group) that is not an ideal?

Let $M=\mathbb{Z} \oplus \mathbb{Z}/4\mathbb{Z}$ as a $\mathbb{Z}$-module. Is M free?

Checking of Subspace

No nontrivial subspaces implies irreducibility of characteristic polynomial

Lifting of principal G-bundles

The definition of finite group scheme.

What is $k[x,y]_{(x,y)}$?

Why is Vakil's definition of "distinguished affine base" of a scheme not a base in the usual sense?

Does being isomorphic to a full subcategory imply being isomorphic to the catgeory

Relation between a universal cover, a fibre, and the fundamental group

Order element of a quotient group