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Jianing Song's user avatar
Jianing Song's user avatar
Jianing Song's user avatar
Jianing Song
  • Member for 2 years, 2 months
  • Last seen this week
7 votes

If $x$ and $y$ are two real quantities connected by the equation $9x^2+2xy+y^2-92x-20y+244=0$ then will $x \in [3,6]$, and $y \in [1,10]$?

5 votes
Accepted

For $0<x<1$, let $f(x)=\int_0^1\left( \left\lfloor\frac{x}{y}\right\rfloor-x \left\lfloor\frac{1}{y}\right\rfloor\right)dy\ldots$

3 votes

Are all algebraic integers with absolute value 1 roots of unity?

2 votes

$U^*\otimes V$ versus $L(U,V)$ for infinite dimensional spaces

2 votes

Why is $\text{Hom}(V,W)$ the same thing as $V^* \otimes W$?

2 votes

Proof of the inequality $e^x \leq x+e^{\frac{9}{16}x^2}$

2 votes
Accepted

Non-Hausdorff topological space where all retract subspaces are closed

1 vote

Give applications of $\beth_3$ other than $\beth_3=\mathcal{P}(\mathcal{P}(\mathcal{P}(\mathbb{N})))$

1 vote
Accepted

What is the expected value of times needed to turn over $n$ cards?

1 vote
Accepted

Find $n$ such that $7^k\mid 3^n+5^n-1$

1 vote
Accepted

Ideals having the same norm as a prime ideal in ring of integers of a number field

1 vote

Do a complex Lie algebra and its realification have the same radical?

1 vote

Find limit of $a_{n+1} = \frac{2a_n}{a_n+1}$.

0 votes

Does the improper integral $\int\limits_0^{+\infty}x^p\sin x\,\mathrm{d}x,~~p>0$ converge?

0 votes

Semisimple Lie algebras are perfect.

0 votes

What are some function spaces that are UFDs?

0 votes

Logarithm Series: Symbol Manipulation Proof that $\log(x) + \log(y) = \log (xy)$

0 votes

The total variation and the integral of the derivative

0 votes

Can groups of automorphism over non-isomorphic groups be isomorphic?

0 votes
Accepted

Does the derivative of a vector-valued BV function $f(x)$ equal to the norm of $f'(x)$?

0 votes
Accepted

Step in Yoshida's proof of Hasse-Arf theorem

0 votes
Accepted

Show that $\left(1-\frac{1}{x}\right)^{\lceil x\ln\left(2\right)\rceil}-\left(1-\frac{2}{x}\right)^{\lceil x\ln\left(2\right)\rceil} \geq \frac{1}{4}$

0 votes

Proving that $ω_1$ is locally compact

0 votes

what is a "powerset" with base larger than 2?

0 votes
Accepted

A family of $\kappa^{<\omega}$ such that for every member in $\kappa$ is contained by all but finitely many elements of the family