User PseudoNeo

3 votes

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For which $n, k$ is $S_{n,k}$ a basis? Fun algebra problem

answered Jan 16, 2015 at 20:30

3 votes

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Is every topological submanifold of codimension $0$ open?

answered Sep 7, 2015 at 16:42

3 votes

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Finding the character table of this group

answered May 18, 2015 at 15:39

3 votes

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Reference for Affine Spaces

answered May 7, 2015 at 10:22

3 votes

For which fields is $\left\{\begin{pmatrix} a & -b \\ b & a \end{pmatrix} \,\middle |\, a, b \in F\right\} \subset M_2(F)$ a field?

answered Oct 14, 2015 at 17:47

3 votes

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Linking Number $0$ When One Knot is a Boundary

answered Jul 5, 2016 at 14:43

3 votes

A question on the non trivial rank three bundle on $S^2$

answered Jul 14, 2016 at 10:24

2 votes

Divergence of sum of reciprocals of square-free numbers

answered Aug 1, 2016 at 8:39

2 votes

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Real Projective $n$ space $\mathbb{R}P^{n}$

answered Jul 14, 2016 at 16:06

2 votes

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Restrictions on homology for compact orientable 3-manifolds

answered Jul 27, 2017 at 21:50

2 votes

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What was Poincaré's original idea of the fundamental group?

answered Nov 20, 2017 at 21:13

2 votes

Is there any formula for $\sum_{k=1}^n k!$?

answered Aug 23, 2016 at 14:38

2 votes

On Steenrod's realization of cycles problem.

answered Jul 12, 2016 at 10:36

2 votes

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Reference about the surgery of Ricci flow

answered Jul 11, 2016 at 17:01

2 votes

What can we say about the function $|f(x)-f(y)|\leq |x-y|^c$ when $c\geq 1$

answered Oct 12, 2015 at 17:02

2 votes

any example shows that coloring number does not equal to clique number?

answered Oct 14, 2015 at 16:54

2 votes

A problem about the alternating group $A_4$

answered Sep 9, 2015 at 17:36

2 votes

Prove/disprove that there are functions $f$ and $g$ that keep the condition, so that if $f$ is surjective and $g$ is injective.

answered Jun 11, 2022 at 21:08

2 votes

Show that $α$ is a perfect square in the quadratic integers in $\mathbb Q[\sqrt{d}]$

answered May 5, 2015 at 13:54

2 votes

$|G|=p_1p_2p_3$ distinct primes with $p_i \nmid p_j-1$ then $G$ is cyclic

answered May 5, 2015 at 14:30

2 votes

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Let $X$ be the figure 8 space embedded in $S^2$. Find $\pi_2(S^2/X)$.

answered May 5, 2015 at 16:26

2 votes

Let $\text{Rank}{(A - \lambda I)^k} = \text{Rank}{(B - \lambda I)^k}$. Why are $A$ and $B$ similar?

answered May 5, 2015 at 16:36

2 votes

Explicit homotopy equivalence of homogeneous spaces $O(2n)/U(n)$ and $GL(2n,\mathbb{R})/GL(n,\mathbb{C})$

answered May 5, 2015 at 1:47

2 votes

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Looking for a "Guide for the Perplexed by Low-dimensional Topology"

answered May 26, 2015 at 9:25

2 votes

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If a square matrix has distinct eigen values, then are the eigen vectors orthogonal?

answered Sep 8, 2015 at 17:48

2 votes

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What does it mean when range is expressed between two "["?

answered Feb 19, 2015 at 9:57

2 votes

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Higher dimensional Jordan-Brower separation theorem

answered Nov 24, 2011 at 9:27

2 votes

Proper normal finite index subgroups

answered Aug 1, 2011 at 23:57

2 votes

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Degree of an odd map

answered Jul 5, 2011 at 11:48

2 votes

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Why is the fundamental group of a prime, reducible 3-manifold $\mathbb{Z}$?

answered Jul 10, 2012 at 19:31

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119 Answers

For which $n, k$ is $S_{n,k}$ a basis? Fun algebra problem

Is every topological submanifold of codimension $0$ open?

Finding the character table of this group

Reference for Affine Spaces

For which fields is $\left\{\begin{pmatrix} a & -b \\ b & a \end{pmatrix} \,\middle |\, a, b \in F\right\} \subset M_2(F)$ a field?

Linking Number $0$ When One Knot is a Boundary

A question on the non trivial rank three bundle on $S^2$

Divergence of sum of reciprocals of square-free numbers

Real Projective $n$ space $\mathbb{R}P^{n}$

Restrictions on homology for compact orientable 3-manifolds

What was Poincaré's original idea of the fundamental group?

Is there any formula for $\sum_{k=1}^n k!$?

On Steenrod's realization of cycles problem.

Reference about the surgery of Ricci flow

What can we say about the function $|f(x)-f(y)|\leq |x-y|^c$ when $c\geq 1$

any example shows that coloring number does not equal to clique number?

A problem about the alternating group $A_4$

Prove/disprove that there are functions $f$ and $g$ that keep the condition, so that if $f$ is surjective and $g$ is injective.

Show that $α$ is a perfect square in the quadratic integers in $\mathbb Q[\sqrt{d}]$

$|G|=p_1p_2p_3$ distinct primes with $p_i \nmid p_j-1$ then $G$ is cyclic

Let $X$ be the figure 8 space embedded in $S^2$. Find $\pi_2(S^2/X)$.

Let $\text{Rank}{(A - \lambda I)^k} = \text{Rank}{(B - \lambda I)^k}$. Why are $A$ and $B$ similar?

Explicit homotopy equivalence of homogeneous spaces $O(2n)/U(n)$ and $GL(2n,\mathbb{R})/GL(n,\mathbb{C})$

Looking for a "Guide for the Perplexed by Low-dimensional Topology"

If a square matrix has distinct eigen values, then are the eigen vectors orthogonal?

What does it mean when range is expressed between two "["?

Higher dimensional Jordan-Brower separation theorem

Proper normal finite index subgroups

Degree of an odd map

Why is the fundamental group of a prime, reducible 3-manifold $\mathbb{Z}$?