User user10354138

31 votes

"Naturally occurring" non-Hausdorff spaces?

answered Aug 3, 2020 at 1:35

21 votes

Accepted

Find the limit $\lim _{n \to \infty}(n!)^{{\frac{1}{n^2}}}$

answered Jun 8, 2019 at 9:14

19 votes

Proving this inequality without calculus

answered Sep 23, 2018 at 17:12

13 votes

Accepted

value of $\int_{-\infty}^{\infty}\arcsin\frac1{\cosh x}\,dx$

answered Oct 31, 2018 at 3:22

13 votes

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Understanding the distance between a line and a point in 3D space

answered Nov 1, 2018 at 0:10

12 votes

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The map from SU(4) to SO(6)

answered Nov 5, 2018 at 10:50

11 votes

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Well ordering principle for rationals

answered Sep 21, 2018 at 7:28

10 votes

Accepted

Does there exist a non-trivial group that is both perfect and complete?

answered Jun 16, 2019 at 14:09

10 votes

Accepted

Let $G$ be a finite group. If $a = bab$, is it true that $b^{2} = e$

answered Nov 1, 2018 at 4:10

9 votes

Fubini's theorem and reparameterisation

answered Sep 27 at 11:05

9 votes

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What is known about merely-orthogonal matrices?

answered Oct 19 at 0:06

9 votes

Accepted

What is the intuition behind pushouts and pullbacks in category theory?

answered Aug 4, 2020 at 13:20

9 votes

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$\sigma$-algebra generated by open balls

answered Aug 8, 2020 at 10:50

9 votes

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Infinite dimensional vector space

answered Jun 17, 2019 at 12:57

9 votes

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Calibrations vs. Riemannian holonomy

answered Jun 18, 2019 at 21:44

9 votes

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Strongest topology that makes vector space locally convex

answered Jun 20, 2019 at 12:55

9 votes

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Evaluating $\int_0^\infty\operatorname{erfi}(x)e^{-x^2}\frac{dx}x$

answered Sep 13, 2018 at 4:50

8 votes

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Is the set of continuous maps on $[0,1]$ with finitely many roots open in the $C^0$ topology?

answered Sep 15 at 21:19

8 votes

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Wish to evaluate $\int_{0}^{1}\frac{x^4-3x^2+2x}{\sin(\pi x)} dx$

answered Jun 13, 2019 at 9:48

8 votes

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What does $\text{Sp}(n)\cdot\text{Sp}(1)$ mean in Berger's holonomy list?

answered Jun 13, 2019 at 17:35

8 votes

If $\lim_{\alpha \to \infty}\alpha P[X > \alpha] = 0$ then $E[X] < \infty$?

answered Aug 7, 2020 at 18:16

8 votes

Accepted

Groups of order $252 = 4 \cdot 7 \cdot 9$ are solvable

answered Aug 5, 2020 at 13:36

7 votes

Accepted

$f$ continuous with derivative $f'(x)=0$ for all $x\in \mathbb{R}\setminus A$ where $A$ is countable implies $f$ constant

answered Sep 25, 2021 at 6:43

7 votes

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Is the intersection of an arbitrary set of finite sets with the finite intersection property nonempty?

answered Oct 7 at 22:01

7 votes

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Dual of an elliptic curve?

answered May 13, 2019 at 6:03

7 votes

Accepted

Evaluate $\sum_{r=1}^{502} \lfloor \frac{305r}{503} \rfloor$.

answered May 16, 2019 at 17:16

7 votes

Accepted

Fundamental group of the real projective plane and its universal cover

answered Jun 7, 2019 at 15:35

7 votes

Find the value of $a_4-a_2$

answered Jun 7, 2019 at 5:38

7 votes

Accepted

Does $G/H\cong \mathbb{Z}^n$ with $H\cong \mathbb{Z}^m$ imply that $G\cong \mathbb{Z}^{m+n}$?

answered Feb 6, 2021 at 14:08

7 votes

Accepted

need help solving a quartic equation

answered Jul 21, 2020 at 14:46

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1,292 Answers

"Naturally occurring" non-Hausdorff spaces?

Find the limit $\lim _{n \to \infty}(n!)^{{\frac{1}{n^2}}}$

Proving this inequality without calculus

value of $\int_{-\infty}^{\infty}\arcsin\frac1{\cosh x}\,dx$

Understanding the distance between a line and a point in 3D space

The map from SU(4) to SO(6)

Well ordering principle for rationals

Does there exist a non-trivial group that is both perfect and complete?

Let $G$ be a finite group. If $a = bab$, is it true that $b^{2} = e$

Fubini's theorem and reparameterisation

What is known about merely-orthogonal matrices?

What is the intuition behind pushouts and pullbacks in category theory?

$\sigma$-algebra generated by open balls

Infinite dimensional vector space

Calibrations vs. Riemannian holonomy

Strongest topology that makes vector space locally convex

Evaluating $\int_0^\infty\operatorname{erfi}(x)e^{-x^2}\frac{dx}x$

Is the set of continuous maps on $[0,1]$ with finitely many roots open in the $C^0$ topology?

Wish to evaluate $\int_{0}^{1}\frac{x^4-3x^2+2x}{\sin(\pi x)} dx$

What does $\text{Sp}(n)\cdot\text{Sp}(1)$ mean in Berger's holonomy list?

If $\lim_{\alpha \to \infty}\alpha P[X > \alpha] = 0$ then $E[X] < \infty$?

Groups of order $252 = 4 \cdot 7 \cdot 9$ are solvable

$f$ continuous with derivative $f'(x)=0$ for all $x\in \mathbb{R}\setminus A$ where $A$ is countable implies $f$ constant

Is the intersection of an arbitrary set of finite sets with the finite intersection property nonempty?

Dual of an elliptic curve?

Evaluate $\sum_{r=1}^{502} \lfloor \frac{305r}{503} \rfloor$.

Fundamental group of the real projective plane and its universal cover

Find the value of $a_4-a_2$

Does $G/H\cong \mathbb{Z}^n$ with $H\cong \mathbb{Z}^m$ imply that $G\cong \mathbb{Z}^{m+n}$?

need help solving a quartic equation