User Darae-Uri

6 votes

1 answer

427 views

For differentiable functions $f,g$, $\nabla f(x)=g(x)x$. Then $f$ is constant on S.

asked Mar 25, 2016 at 12:17

5 votes

3 answers

301 views

How can I show that $G$ is non abelian of order 20?

asked Apr 25, 2016 at 10:44

5 votes

2 answers

2k views

Characterisation of limit points of subsets of Hausdorff spaces

asked Apr 11, 2015 at 4:42

4 votes

1 answer

3k views

$Aut(G)$ is abelian if and only if $G$ is cyclic. [duplicate]

asked May 3, 2016 at 11:27

4 votes

1 answer

2k views

A group-ring is commutative if and only if that group is abelian

asked May 6, 2016 at 5:57

3 votes

1 answer

5k views

$G\oplus H$ is cyclic iff finite groups $G$ and $H$ are cyclic and $\gcd(|G|,|H|)=1$

asked Mar 19, 2016 at 10:25

3 votes

3 answers

5k views

Show that $R_P$ has a unique maximal ideal

asked Jun 10, 2016 at 18:06

3 votes

1 answer

107 views

Exercise from mathematical Logic about length of sentences in SL

asked Sep 2, 2015 at 11:33

3 votes

1 answer

178 views

How to show $T=\{\forall x(x\neq S^{n}x)|1\leq n\}\cup\{\sigma\}$ in $\mathcal{L}=\{S\}$ is $\kappa$-categorical

asked Nov 22, 2015 at 10:52

3 votes

1 answer

96 views

What is the automorphism on $\mathbb R$ which maps $\pi$ to $-\pi$?

asked Sep 29, 2016 at 16:01

2 votes

0 answers

219 views

Find the orbits of the action of $\mathrm{Aut}(G)$ on $G$.

asked Nov 6, 2016 at 16:22

2 votes

1 answer

2k views

What is area form?

asked Jun 17, 2016 at 15:36

2 votes

1 answer

237 views

List out all the definable set in given model

asked Oct 2, 2015 at 8:58

2 votes

1 answer

74 views

How to prove UG is sound?

asked May 31, 2015 at 8:33

2 votes

1 answer

399 views

Simple exercise in differential geometry

asked Mar 5, 2016 at 13:27

2 votes

1 answer

40 views

Simple calculation of integration

asked Nov 11, 2015 at 12:44

2 votes

1 answer

3k views

Formula for composition of pull back

asked May 24, 2016 at 23:41

2 votes

0 answers

76 views

Show that $(\mathbb{Z}\oplus\mathbb{Z})[x]$ is not isomorphic to $\mathbb{Z}[x]\oplus\mathbb{Z}[x] $ . [duplicate]

asked May 31, 2016 at 6:56

2 votes

1 answer

397 views

$Df(x_0)$ is nonzero $\Rightarrow $invertible. What about the reverse?

asked May 10, 2016 at 11:50

2 votes

0 answers

43 views

Taylor's Theorem for a function whose domain is $\mathbb R^n$

asked Mar 27, 2016 at 5:35

1 vote

1 answer

519 views

Determining the number and order of all cyclic subgroup $Z_5 \oplus Z_{15}$

asked Mar 28, 2016 at 13:35

1 vote

0 answers

204 views

How to prove Rouche's theorem in $\mathbb R^2$

asked May 15, 2016 at 15:37

1 vote

3 answers

126 views

How to show that for any $r>0$ , $\lim_{n\rightarrow\infty}\int_{\mathbb{R}\backslash[-r,r]}\sqrt{\frac{n}{\pi}}e^{-nx^{2}}=0 $

asked Jun 6, 2016 at 6:31

1 vote

1 answer

160 views

Uniform convergence of $\sum_{n=1}^{\infty}x^{n}/n^{2}$

asked Nov 16, 2015 at 9:30

1 vote

1 answer

119 views

how to show that $n^k x^n$ is convergent?

asked Nov 18, 2015 at 6:57

1 vote

0 answers

229 views

How to show that F is recursive?

asked Nov 20, 2015 at 11:41

1 vote

1 answer

175 views

How to show that there is a deduction of $\varphi\leftrightarrow\psi$

asked Sep 15, 2015 at 13:59

1 vote

1 answer

7k views

Proving $k^{m+l} = k^m k^l$ by constructing a bijective function F : $ ^MK \times ^LK \to ^{L\bigcup M}K $

asked May 21, 2015 at 10:05

1 vote

4 answers

101 views

How to show that $f_{n}(x)=\frac{x^{2}}{x^{2}+(1-nx)^{2}},\,0\leq x\leq1 $ is not uniformly convergent

asked Dec 1, 2015 at 14:27

1 vote

1 answer

293 views

Automorphism for definable set [duplicate]

asked Oct 6, 2015 at 14:01

Stack Exchange Network

43 Questions

For differentiable functions $f,g$, $\nabla f(x)=g(x)x$. Then $f$ is constant on S.

How can I show that $G$ is non abelian of order 20?

Characterisation of limit points of subsets of Hausdorff spaces

$Aut(G)$ is abelian if and only if $G$ is cyclic. [duplicate]

A group-ring is commutative if and only if that group is abelian

$G\oplus H$ is cyclic iff finite groups $G$ and $H$ are cyclic and $\gcd(|G|,|H|)=1$

Show that $R_P$ has a unique maximal ideal

Exercise from mathematical Logic about length of sentences in SL

How to show $T=\{\forall x(x\neq S^{n}x)|1\leq n\}\cup\{\sigma\}$ in $\mathcal{L}=\{S\}$ is $\kappa$-categorical

What is the automorphism on $\mathbb R$ which maps $\pi$ to $-\pi$?

Find the orbits of the action of $\mathrm{Aut}(G)$ on $G$.

What is area form?

List out all the definable set in given model

How to prove UG is sound?

Simple exercise in differential geometry

Simple calculation of integration

Formula for composition of pull back

Show that $(\mathbb{Z}\oplus\mathbb{Z})[x]$ is not isomorphic to $\mathbb{Z}[x]\oplus\mathbb{Z}[x] $ . [duplicate]

$Df(x_0)$ is nonzero $\Rightarrow $invertible. What about the reverse?

Taylor's Theorem for a function whose domain is $\mathbb R^n$

Determining the number and order of all cyclic subgroup $Z_5 \oplus Z_{15}$

How to prove Rouche's theorem in $\mathbb R^2$

How to show that for any $r>0$ , $\lim_{n\rightarrow\infty}\int_{\mathbb{R}\backslash[-r,r]}\sqrt{\frac{n}{\pi}}e^{-nx^{2}}=0 $

Uniform convergence of $\sum_{n=1}^{\infty}x^{n}/n^{2}$

how to show that $n^k x^n$ is convergent?

How to show that F is recursive?

How to show that there is a deduction of $\varphi\leftrightarrow\psi$

Proving $k^{m+l} = k^m k^l$ by constructing a bijective function F : $ ^MK \times ^LK \to ^{L\bigcup M}K $

How to show that $f_{n}(x)=\frac{x^{2}}{x^{2}+(1-nx)^{2}},\,0\leq x\leq1 $ is not uniformly convergent

Automorphism for definable set [duplicate]