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fhyve
  • Member for 11 years, 7 months
  • Last seen more than 5 years ago
48 votes
2 answers
50k views

Bijection from $\mathbb R$ to $\mathbb {R^N}$

20 votes
5 answers
5k views

What does it mean for something to be true but not provable in peano arithmetic?

18 votes
1 answer
2k views

Constructing a bijection from (0,1) to the irrationals in (0,1)

12 votes
3 answers
1k views

Currently, what is the largest publicly known prime number such that all prime numbers less than it are known?

10 votes
1 answer
4k views

Meaning of quote: "model theory = algebraic geometry - fields"?

8 votes
2 answers
7k views

What is the fastest (most reliable) way to calculate the Frenet frame, curvature and torsion, given r(t)?

7 votes
1 answer
293 views

Path to categorical realizability theory

6 votes
1 answer
283 views

All translations of classical logic into intuitionistic logic

6 votes
9 answers
3k views

There exists a rational sequence that converges to $\sqrt3$

5 votes
3 answers
8k views

Without Lagrange's theorem: If $H$ is a subgroup of odd order of $S_n$, then it is a subgroup of $A_n$.

5 votes
2 answers
348 views

Interaction of completeness and second incompleteness theorems

4 votes
0 answers
136 views

Are there any texts on order theory that treat it as decategorified category theory?

4 votes
0 answers
212 views

$Gal(\bar{\mathbb Q}/\mathbb Q)$ without choice, and constructive Galois theory

4 votes
3 answers
560 views

If prime $p\not \equiv 1 \pmod 3$, then $p^2 = a^2 + ab + b^2$ has no solutions $a,\,b \in \mathbb{N} \}$

4 votes
1 answer
103 views

How to reason about congruences? If $x^2 \equiv a$ (mod $m$) and $y^3 \equiv a$ (mod $m$), then $\gcd(a,m) = 1$

4 votes
1 answer
107 views

Prove that the only solution to $n | (3^{n-1})^2 + 3^{n-1} + 1$ is $n = 1$.

3 votes
3 answers
2k views

If $g \circ f$ is monic, then $f$ is monic

3 votes
4 answers
13k views

Prove that $\frac{2^n}{n!}$ converges 0. [duplicate]

3 votes
2 answers
1k views

If $f: A \rightarrow B$ is injective, $\exists ! f^{-1}:f(A)\rightarrow A$ such that $f^{-1}f(x) = x$

3 votes
1 answer
103 views

Projection $\pi : (x,y) \mapsto x$ of $V(y^2 - g(x))$ where g is cubic extends to a regular map of the projective closure

3 votes
2 answers
101 views

Logic with finite symbols

2 votes
2 answers
53 views

Compatible intersecting coordinate patches must map to the same dimensional $\mathbb R^n$.

2 votes
1 answer
6k views

What is the Poisson integral formula for?

2 votes
1 answer
510 views

Extensions of quasicoherent sheaves are quasicoherent.

2 votes
2 answers
2k views

Binary string that contains all substrings of length k exactly once.

2 votes
1 answer
7k views

Let $f(x) = x^2 \sin (1/x^2),\,x\ne 0,$ and $ f(0)=0.$ Prove $f$ is differentiable on $\mathbb R$

2 votes
1 answer
253 views

Sequence of vectors spaces of linear transformations of vector spaces.

2 votes
1 answer
304 views

Integer polynomial, maximum number of consecutive integer values that it can reach.

1 vote
2 answers
270 views

Sur- in- bijections and cardinality.

1 vote
2 answers
95 views

Are $\forall x \in A, \exists y \in B, p(x,y)$ and $\exists f \in B^{A}, \forall x \in A, p(x,f(x))$ equivalent?