User PseudoNeo

59 votes

2 answers

5k views

Axiom of choice and automorphisms of vector spaces

asked Mar 20, 2011 at 16:49

21 votes

4 answers

1k views

Manageable project to learn some arithmetic geometry

asked Mar 21, 2021 at 14:56

16 votes

3 answers

2k views

Binary tetrahedral group and $\rm{SL}_2(\mathbb F_3)$

asked Apr 24, 2013 at 14:17

14 votes

2 answers

4k views

Is the quotient map a homotopy equivalence?

asked Nov 15, 2013 at 15:41

13 votes

1 answer

537 views

The Wronskian of holomorphic differentials as a q-differential

asked May 3, 2011 at 16:00

12 votes

0 answers

522 views

How do I know if an irreducible representation is a permutation representation?

asked Nov 11, 2017 at 1:18

11 votes

1 answer

178 views

Diffeomorphism-invariant spaces of smooth functions

asked May 26, 2015 at 13:09

11 votes

3 answers

1k views

Differentiable at a point

asked Mar 1, 2011 at 19:30

8 votes

1 answer

2k views

Irreducibility of $X^n - 2$ over $\mathbf Z[i]$.

asked Jan 21, 2013 at 20:37

8 votes

2 answers

202 views

Syndeticity- and thickness-preserving bijections of $\mathbb N$

asked Sep 21, 2021 at 8:25

8 votes

1 answer

139 views

Erratum in Kossak's "Model theory for beginners"

asked Feb 19 at 9:53

7 votes

1 answer

389 views

How many coefficients do you have to change to lower the rank of a matrix?

asked Jul 27, 2017 at 2:05

6 votes

0 answers

260 views

What does it take to have a precise definition of volume?

asked Jan 29, 2016 at 14:43

6 votes

1 answer

367 views

Minimal example of Simpson's paradox

asked Apr 14, 2019 at 17:59

5 votes

0 answers

209 views

Weighted polynomial approximation on the half-line

asked Sep 22, 2017 at 23:57

5 votes

1 answer

1k views

Easy proof of a weak form of Mertens's second theorem

asked Mar 6, 2018 at 5:17

5 votes

1 answer

348 views

Center of the unit group $R^\times$ of a ring.

asked Mar 27, 2013 at 7:59

5 votes

1 answer

1k views

Ring of analytic functions on the circle

asked Jun 6, 2012 at 9:30

5 votes

1 answer

540 views

Is the intersection of two f.g. projective submodules f.g.?

asked Aug 1, 2012 at 21:57

4 votes

1 answer

651 views

Is the kernel of a linear form $f : A^n \to A$ a projective module?

asked Mar 22, 2012 at 14:56

4 votes

2 answers

198 views

Connectedness arguments in elementary mathematics?

asked Jan 7, 2015 at 11:17

3 votes

1 answer

962 views

Matrices: injectivity and determinant

asked Feb 14, 2011 at 21:10

2 votes

0 answers

71 views

Weird analogy between quadratic forms and formal systems

asked Apr 11, 2017 at 23:10

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23 Questions

Axiom of choice and automorphisms of vector spaces

Manageable project to learn some arithmetic geometry

Binary tetrahedral group and $\rm{SL}_2(\mathbb F_3)$

Is the quotient map a homotopy equivalence?

The Wronskian of holomorphic differentials as a q-differential

How do I know if an irreducible representation is a permutation representation?

Diffeomorphism-invariant spaces of smooth functions

Differentiable at a point

Irreducibility of $X^n - 2$ over $\mathbf Z[i]$.

Syndeticity- and thickness-preserving bijections of $\mathbb N$

Erratum in Kossak's "Model theory for beginners"

How many coefficients do you have to change to lower the rank of a matrix?

What does it take to have a precise definition of volume?

Minimal example of Simpson's paradox

Weighted polynomial approximation on the half-line

Easy proof of a weak form of Mertens's second theorem

Center of the unit group $R^\times$ of a ring.

Ring of analytic functions on the circle

Is the intersection of two f.g. projective submodules f.g.?

Is the kernel of a linear form $f : A^n \to A$ a projective module?

Connectedness arguments in elementary mathematics?

Matrices: injectivity and determinant

Weird analogy between quadratic forms and formal systems