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PseudoNeo
  • Member for 13 years, 5 months
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8 votes
1 answer
133 views

Erratum in Kossak's "Model theory for beginners"

8 votes
2 answers
202 views

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

21 votes
4 answers
1k views

Manageable project to learn some arithmetic geometry

6 votes
1 answer
365 views

Minimal example of Simpson's paradox

5 votes
1 answer
1k views

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

12 votes
0 answers
519 views

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

5 votes
0 answers
208 views

Weighted polynomial approximation on the half-line

7 votes
1 answer
382 views

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

2 votes
0 answers
70 views

Weird analogy between quadratic forms and formal systems

6 votes
0 answers
254 views

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

11 votes
1 answer
176 views

Diffeomorphism-invariant spaces of smooth functions

4 votes
2 answers
196 views

Connectedness arguments in elementary mathematics?

13 votes
2 answers
4k views

Is the quotient map a homotopy equivalence?

16 votes
3 answers
2k views

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

5 votes
1 answer
347 views

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

8 votes
1 answer
2k views

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

5 votes
1 answer
539 views

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

5 votes
1 answer
1k views

Ring of analytic functions on the circle

4 votes
1 answer
649 views

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

13 votes
1 answer
537 views

The Wronskian of holomorphic differentials as a q-differential

59 votes
2 answers
5k views

Axiom of choice and automorphisms of vector spaces

11 votes
3 answers
1k views

Differentiable at a point

3 votes
1 answer
960 views

Matrices: injectivity and determinant