User Daniel Teixeira

6 votes

2 answers

138 views

Give a reason why $\mathbb Z_{64}\times \mathbb Z_4$ and $\mathbb Z_{64}\times \mathbb Z_{2}\times \mathbb Z_{2}$ are not isomorphic.

asked Dec 31, 2020 at 22:14

5 votes

2 answers

375 views

Completeness of the category of enriched categories

asked Apr 15, 2020 at 18:48

5 votes

0 answers

152 views

Why do we care about $(\infty,2)$-categories?

asked Aug 9, 2021 at 18:08

4 votes

2 answers

102 views

Show that $\mathbb{Z}_5[x]/(x^2+x+1)\cong\mathbb{Z}_5[x]/(x^2+x+2)$

asked Sep 18, 2018 at 22:18

3 votes

1 answer

258 views

In $\mathbb{Z}[\sqrt{d}]$, $d$ is not divisible by the square of any prime. Why?

asked Oct 24, 2018 at 18:49

3 votes

1 answer

123 views

Explicit homeomorphism $SL(2,\mathbb{C})\cong SU(2)\times\mathbb{R}^3$.

asked Jun 28, 2019 at 14:05

3 votes

0 answers

96 views

Linear algebra constructions on vector bundles

asked Jul 28, 2020 at 14:53

3 votes

0 answers

64 views

Why $T_pM$ instead of $TM_p$?

asked Sep 16, 2020 at 14:25

3 votes

0 answers

65 views

Why are acyclic fibrations called so?

asked Sep 18, 2020 at 13:20

3 votes

1 answer

53 views

For $n\geq 3$, does every horn $\Lambda^n_k\to N\mathcal C$ have a filler?

asked Dec 14, 2020 at 15:47

2 votes

0 answers

82 views

Localization of a ring at any subset

asked Nov 26, 2021 at 20:17

2 votes

0 answers

50 views

Show that $\text{Top}$ is locally Kan.

asked Feb 8, 2021 at 14:18

2 votes

0 answers

46 views

Cycles in an acyclic complex of projectives are projectives.

asked Feb 12, 2021 at 19:21

2 votes

1 answer

129 views

Monoidal categories as categories internal to $\textbf{Cat}$

asked Apr 12, 2020 at 13:21

2 votes

1 answer

160 views

Are simplicial sets equal if their non-degenerate simplices are the same?

asked Dec 9, 2020 at 22:41

2 votes

1 answer

247 views

Show that $\int |f_n-f|\to 0$

asked Jan 2, 2021 at 18:10

2 votes

1 answer

334 views

Is there an $\infty$-category of spaces?

asked Jan 13, 2021 at 20:39

2 votes

1 answer

71 views

Canonical model structure on a 2-category

asked Sep 16, 2020 at 14:48

2 votes

1 answer

40 views

$V^{1,0}$ as a Lagrangian subspace of $V^c$

asked Aug 24, 2020 at 20:58

2 votes

1 answer

82 views

Inductive definition of $\infty$-category

asked Apr 18, 2020 at 14:06

2 votes

1 answer

156 views

A ring is commutative if the solution of $ab=ca$ is always unique [duplicate]

asked Aug 22, 2018 at 19:41

2 votes

3 answers

465 views

Flat principal bundles over a simply connected manifold are trivial

asked Oct 16, 2019 at 18:41

2 votes

0 answers

55 views

Surfaces of revolution as vector bundles

asked Mar 7, 2018 at 14:39

2 votes

0 answers

132 views

Invariance of signature in semi-riemannian manifolds

asked Jun 27, 2018 at 18:27

1 vote

1 answer

35 views

The projection from the time-orientable double cover preserves topological properties.

asked Jun 27, 2018 at 23:59

1 vote

0 answers

199 views

Using the Fourier transform to solve PDEs with non-integrable initial conditions

asked Nov 13, 2017 at 5:03

1 vote

1 answer

37 views

Can a data set of a function $f:\mathbb{R}^n\to\mathbb{R}^k$ decide if it is differentiable?

asked Apr 20, 2018 at 15:07

1 vote

2 answers

41 views

Let $C\subset E$ be a convex subspace and $a\in E\setminus C$. The point in $C$ closest to $a$ is unique.

asked Apr 20, 2018 at 19:16

1 vote

0 answers

41 views

Vacuum solutions of Einstein's field equations with $O(n)$ isometry group

asked Jun 27, 2018 at 13:21

1 vote

0 answers

59 views

Definition of tensor product of graded maps

asked Mar 20, 2020 at 14:37

Stack Exchange Network

39 Questions

Give a reason why $\mathbb Z_{64}\times \mathbb Z_4$ and $\mathbb Z_{64}\times \mathbb Z_{2}\times \mathbb Z_{2}$ are not isomorphic.

Completeness of the category of enriched categories

Why do we care about $(\infty,2)$-categories?

Show that $\mathbb{Z}_5[x]/(x^2+x+1)\cong\mathbb{Z}_5[x]/(x^2+x+2)$

In $\mathbb{Z}[\sqrt{d}]$, $d$ is not divisible by the square of any prime. Why?

Explicit homeomorphism $SL(2,\mathbb{C})\cong SU(2)\times\mathbb{R}^3$.

Linear algebra constructions on vector bundles

Why $T_pM$ instead of $TM_p$?

Why are acyclic fibrations called so?

For $n\geq 3$, does every horn $\Lambda^n_k\to N\mathcal C$ have a filler?

Localization of a ring at any subset

Show that $\text{Top}$ is locally Kan.

Cycles in an acyclic complex of projectives are projectives.

Monoidal categories as categories internal to $\textbf{Cat}$

Are simplicial sets equal if their non-degenerate simplices are the same?

Show that $\int |f_n-f|\to 0$

Is there an $\infty$-category of spaces?

Canonical model structure on a 2-category

$V^{1,0}$ as a Lagrangian subspace of $V^c$

Inductive definition of $\infty$-category

A ring is commutative if the solution of $ab=ca$ is always unique [duplicate]

Flat principal bundles over a simply connected manifold are trivial

Surfaces of revolution as vector bundles

Invariance of signature in semi-riemannian manifolds

The projection from the time-orientable double cover preserves topological properties.

Using the Fourier transform to solve PDEs with non-integrable initial conditions

Can a data set of a function $f:\mathbb{R}^n\to\mathbb{R}^k$ decide if it is differentiable?

Let $C\subset E$ be a convex subspace and $a\in E\setminus C$. The point in $C$ closest to $a$ is unique.

Vacuum solutions of Einstein's field equations with $O(n)$ isometry group

Definition of tensor product of graded maps