User BHT

3 votes

Accepted

A "counterexample" of uniform boundedness theorem

answered Nov 29, 2023 at 22:22

1 vote

Prove that if $f: \mathbb{R} \to \mathbb{R}$ is convex and bounded from above, then $f$ is constant.

answered Nov 29, 2023 at 22:02

2 votes

Accepted

Prove a beta-function-related formula, using induction

answered Nov 16, 2023 at 20:46

0 votes

Example of a linear map over $\mathbb R(X)$ which isn't a linear map over $C^1$

answered Nov 11, 2020 at 1:12

0 votes

property of a normal subgroup of a transively group acting on a set $S$

answered Nov 11, 2020 at 0:58

1 vote

How a linear function is bounded below on $R^n$ only when it is zero and not -$\infty$?

answered Oct 27, 2020 at 21:51

0 votes

Irreducibility in $\mathbb{Z}[\sqrt{10}]$. and modular arithmetic

answered Apr 12, 2020 at 21:12

2 votes

Series $\sum(n^2+dm^2)^{-s}$ and its relation to unique decomposability of $\mathbb Z[\sqrt{-d}]$

answered Apr 10, 2020 at 23:02

1 vote

Accepted

Euler Theorem and Modular Inverse for Non Coprime Problem

answered Apr 8, 2020 at 12:47

1 vote

Prove that no solution exists for $ \frac{dx}{dt} = f(x), x(0)=0,$ where $f(x) =1$ if $x<0$ and $= -1 $ if $x \geq 0$.

answered Apr 8, 2020 at 1:47

1 vote

A Selberg's sieve application

answered Apr 8, 2020 at 1:29

0 votes

Cancellation for Field Extensions

answered Apr 7, 2020 at 23:37

3 votes

Accepted

does a slight change in a real value cause a massive change from finite to infinite?

answered Apr 7, 2020 at 23:00

0 votes

Euler Theorem and Modular Inverse for Non Coprime Problem

answered Apr 7, 2020 at 22:49

1 vote

Accepted

Submodules of finite type

answered Apr 5, 2020 at 4:36

0 votes

Deducing that $cos( \frac{2π}{5}) = \frac{-1+ \sqrt{5}}{4}$

answered Apr 7, 2019 at 20:39

4 votes

Accepted

Showing that the tribonacci sequence has relatively prime terms

answered Mar 27, 2019 at 4:01

3 votes

Accepted

Does $(x+1)^p \not \equiv_p x^p + 1$ for some $x$ hold if $p$ isn't prime?

answered Mar 20, 2019 at 23:50

2 votes

Accepted

Why isn't $(x+1)^p \equiv_q x^p + 1$ if $q$ is a prime factor of $p$?

answered Mar 20, 2019 at 20:24

4 votes

Accepted

Solve the Diophantine equation $24x^4-5y^4=z^2$

answered Mar 19, 2019 at 6:19

1 vote

Accepted

Entropy of the upper and lower bits of a square number

answered Mar 18, 2019 at 14:01

1 vote

is this convex inequality possibly true?

answered Mar 18, 2019 at 9:22

57 votes

Accepted

Does convergence of polynomials imply that of its coefficients?

answered Mar 18, 2019 at 8:32

3 votes

Accepted

Nilradical geometrical way of thinking about it

answered Feb 22, 2017 at 1:40

3 votes

Accepted

Dimension of the quotient of a local ring

answered Feb 16, 2017 at 3:38

5 votes

Accepted

Irreducible Spectrum implies Zero-Divisors are Nilpotent

answered Feb 13, 2017 at 0:05

0 votes

How far is the point where the rear ends of the two trains cross each other given the following conditions?

answered Oct 7, 2015 at 14:53

1 vote

How to write $\displaystyle\prod_{i<j} (j-i)$ as an explicit sum?

answered Mar 1, 2015 at 21:10

0 votes

Is the Legendre transformation just simple substitution?

answered Feb 6, 2015 at 5:11

2 votes

Accepted

What are the standard defintions of "counterclockwise" and "clockwise" in 3d space?

answered Jan 31, 2015 at 3:50

Stack Exchange Network

40 Answers

A "counterexample" of uniform boundedness theorem

Prove that if $f: \mathbb{R} \to \mathbb{R}$ is convex and bounded from above, then $f$ is constant.

Prove a beta-function-related formula, using induction

Example of a linear map over $\mathbb R(X)$ which isn't a linear map over $C^1$

property of a normal subgroup of a transively group acting on a set $S$

How a linear function is bounded below on $R^n$ only when it is zero and not -$\infty$?

Irreducibility in $\mathbb{Z}[\sqrt{10}]$. and modular arithmetic

Series $\sum(n^2+dm^2)^{-s}$ and its relation to unique decomposability of $\mathbb Z[\sqrt{-d}]$

Euler Theorem and Modular Inverse for Non Coprime Problem

Prove that no solution exists for $ \frac{dx}{dt} = f(x), x(0)=0,$ where $f(x) =1$ if $x<0$ and $= -1 $ if $x \geq 0$.

A Selberg's sieve application

Cancellation for Field Extensions

does a slight change in a real value cause a massive change from finite to infinite?

Euler Theorem and Modular Inverse for Non Coprime Problem

Submodules of finite type

Deducing that $cos( \frac{2π}{5}) = \frac{-1+ \sqrt{5}}{4}$

Showing that the tribonacci sequence has relatively prime terms

Does $(x+1)^p \not \equiv_p x^p + 1$ for some $x$ hold if $p$ isn't prime?

Why isn't $(x+1)^p \equiv_q x^p + 1$ if $q$ is a prime factor of $p$?

Solve the Diophantine equation $24x^4-5y^4=z^2$

Entropy of the upper and lower bits of a square number

is this convex inequality possibly true?

Does convergence of polynomials imply that of its coefficients?

Nilradical geometrical way of thinking about it

Dimension of the quotient of a local ring

Irreducible Spectrum implies Zero-Divisors are Nilpotent

How far is the point where the rear ends of the two trains cross each other given the following conditions?

How to write $\displaystyle\prod_{i<j} (j-i)$ as an explicit sum?

Is the Legendre transformation just simple substitution?

What are the standard defintions of "counterclockwise" and "clockwise" in 3d space?