User Jeong

16 votes

1 answer

6k views

A covering space of CW complex has an induced CW complex structure.

asked Jul 28, 2015 at 0:41

9 votes

1 answer

776 views

Ring homomorphism of tensor product of algebras

asked Jul 1, 2015 at 4:20

7 votes

1 answer

286 views

Existence of a smooth time-dependent 1-form $\mu_t$ satisfying $\omega_t = d \mu_t$ for a given smooth time-dependent exact 2-form

asked Sep 13, 2016 at 22:00

5 votes

1 answer

1k views

$GL(n, \mathbb{C})$ is a properly embedded Lie subgroup of $GL(2n, \mathbb{R})$

asked Nov 7, 2015 at 4:12

5 votes

1 answer

1k views

The restriction fo covering to a component is a covering map onto its image.

asked Jul 25, 2015 at 8:39

5 votes

1 answer

352 views

Exercise 1.13 of II in Hartshorne algebraic geometry.

asked May 19, 2015 at 18:19

5 votes

1 answer

2k views

Exercise $1.8$ of chapter one in Hartshorne.

asked Jun 6, 2015 at 14:53

4 votes

2 answers

881 views

Gaussian Curvature of $x^4+y^4+z^4=1$

asked Jun 25, 2015 at 22:31

4 votes

2 answers

874 views

Distributive law of ideals in $\mathbf Z$ relating $\cap$ and $+$.

asked Jun 4, 2015 at 0:44

4 votes

2 answers

856 views

$n$-th derivative of $(x^2-1)^n$ has distinct real roots in $[-1,1]$.

asked Jul 31, 2015 at 12:36

3 votes

3 answers

1k views

Is $f(x) = x^3 \sin \frac{1}{x} $ uniformly continuous on $(0, \infty)$?

asked Aug 24, 2015 at 8:22

3 votes

2 answers

116 views

Does $p^n$ divide $\binom{p^{n+m-1}}{m}$?

asked Jun 11, 2015 at 13:12

3 votes

0 answers

77 views

Zero elements of tensor product of two free modules

asked Dec 5, 2016 at 17:30

3 votes

1 answer

366 views

A doubt in the proof of Noether's normalization lemma.

asked Mar 14, 2017 at 7:54

3 votes

1 answer

121 views

Involutivity of $TS^{\perp} \subseteq TS$, where $S$ is a coisotropic submanifold of a symplectic manifold $(M,\omega)$

asked Sep 19, 2016 at 18:31

3 votes

1 answer

161 views

Is $t^3+t+1$ irreducible over $\mathbb{Q}(\sqrt{-31})$?

asked Sep 26, 2015 at 1:25

3 votes

2 answers

800 views

Under what $p$, $-1$ is a square in $\mathbf F_p$? [duplicate]

asked Jun 14, 2015 at 14:12

3 votes

1 answer

200 views

Definition of positive definite matrix

asked Apr 11, 2017 at 18:23

3 votes

1 answer

205 views

Finding a domain of an integral curve of a vector field

asked Jan 30, 2016 at 18:17

2 votes

1 answer

86 views

On the definition of Universes.

asked Apr 28, 2017 at 8:06

2 votes

1 answer

136 views

A question on the half-full functor

asked Apr 2, 2018 at 17:14

2 votes

1 answer

59 views

$\beta_1 \gamma_1 {\beta_1}^{-1}{\gamma_1}^{-1}$ is not null-homotopic in the two-holed torus.

asked Oct 12, 2015 at 4:36

2 votes

1 answer

89 views

The normal closure of $\mathbb{Q}(\alpha)$ with degree a power of 2 is in $\mathbb{R}$

asked Sep 27, 2015 at 3:38

2 votes

2 answers

243 views

Derivative of an exact form $\omega_t$ is still exact?

asked Mar 16, 2017 at 5:11

2 votes

1 answer

114 views

$S^2 / (\text{pseudo-circle}) \approx S^2 \vee S^2$

asked Dec 26, 2016 at 23:34

2 votes

0 answers

350 views

Regarding Espace Etale of a presheaf, is $\bar s$ an open map?

asked May 19, 2015 at 14:31

2 votes

1 answer

240 views

The limit of a series of continous functions is continuous.

asked Aug 5, 2015 at 12:02

2 votes

0 answers

597 views

Homotopic maps between connected spaces inducing the same homomorphism between the fundamental groups

asked Jul 9, 2015 at 11:21

1 vote

1 answer

109 views

If $f\in C^2(\mathbb R)$ then $M_1^2 \le 2M_0 M_2$, where $M_k = \text {sup}_x |(d/dx)^k f(x)|$ for $k=0,1,2.$ [duplicate]

asked Aug 26, 2015 at 5:15

1 vote

1 answer

132 views

Decompose $\mathbb {Z}_{pq}^* / (\mathbb {Z}_{pq}^*)^2$ into a direct sum of cyclic groups.

asked Sep 16, 2015 at 21:03

Stack Exchange Network

44 Questions

A covering space of CW complex has an induced CW complex structure.

Ring homomorphism of tensor product of algebras

Existence of a smooth time-dependent 1-form $\mu_t$ satisfying $\omega_t = d \mu_t$ for a given smooth time-dependent exact 2-form

$GL(n, \mathbb{C})$ is a properly embedded Lie subgroup of $GL(2n, \mathbb{R})$

The restriction fo covering to a component is a covering map onto its image.

Exercise 1.13 of II in Hartshorne algebraic geometry.

Exercise $1.8$ of chapter one in Hartshorne.

Gaussian Curvature of $x^4+y^4+z^4=1$

Distributive law of ideals in $\mathbf Z$ relating $\cap$ and $+$.

$n$-th derivative of $(x^2-1)^n$ has distinct real roots in $[-1,1]$.

Is $f(x) = x^3 \sin \frac{1}{x} $ uniformly continuous on $(0, \infty)$?

Does $p^n$ divide $\binom{p^{n+m-1}}{m}$?

Zero elements of tensor product of two free modules

A doubt in the proof of Noether's normalization lemma.

Involutivity of $TS^{\perp} \subseteq TS$, where $S$ is a coisotropic submanifold of a symplectic manifold $(M,\omega)$

Is $t^3+t+1$ irreducible over $\mathbb{Q}(\sqrt{-31})$?

Under what $p$, $-1$ is a square in $\mathbf F_p$? [duplicate]

Definition of positive definite matrix

Finding a domain of an integral curve of a vector field

On the definition of Universes.

A question on the half-full functor

$\beta_1 \gamma_1 {\beta_1}^{-1}{\gamma_1}^{-1}$ is not null-homotopic in the two-holed torus.

The normal closure of $\mathbb{Q}(\alpha)$ with degree a power of 2 is in $\mathbb{R}$

Derivative of an exact form $\omega_t$ is still exact?

$S^2 / (\text{pseudo-circle}) \approx S^2 \vee S^2$

Regarding Espace Etale of a presheaf, is $\bar s$ an open map?

The limit of a series of continous functions is continuous.

Homotopic maps between connected spaces inducing the same homomorphism between the fundamental groups

If $f\in C^2(\mathbb R)$ then $M_1^2 \le 2M_0 M_2$, where $M_k = \text {sup}_x |(d/dx)^k f(x)|$ for $k=0,1,2.$ [duplicate]

Decompose $\mathbb {Z}_{pq}^* / (\mathbb {Z}_{pq}^*)^2$ into a direct sum of cyclic groups.