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Hagrid
  • Member for 9 years, 7 months
  • Last seen more than 3 years ago
25 votes
3 answers
4k views

Riemann rearrangement theorem

20 votes
1 answer
2k views

Inverse of a bijection f is equal to its derivative

11 votes
2 answers
2k views

Barycentric coordinates in a triangle - proof

9 votes
1 answer
8k views

Prove that if a continuous function is injective, then it is monotonic

9 votes
2 answers
5k views

Number of $n$-digit palindromes

7 votes
1 answer
683 views

Graph, two colors, no path length 3

7 votes
1 answer
308 views

What functions satisfy $\sum _{n=1} ^{\infty} x_n < \infty \ \Rightarrow \sum _{n=1} ^{\infty} f(x_n) < \infty $ [duplicate]

6 votes
1 answer
1k views

Prove that any function can be represented as a sum of two injections

6 votes
3 answers
2k views

Classification of Euclidean plane isometries

6 votes
4 answers
506 views

Evaluating $\lim _{n \rightarrow \infty} (2n+1) \int_0 ^{1} x^n e^x dx$

6 votes
1 answer
473 views

Biholomorphic map from a disk to its quarter

5 votes
2 answers
355 views

Normed separable space, linearly independent $X_0 \subset X, \ \overline{linX_0} = X $

5 votes
1 answer
1k views

Implicit function, not obvious version

5 votes
0 answers
264 views

Sigma algebra generated by a homeomorphic random variable

5 votes
2 answers
3k views

Sum of discrete and continuous random variables with uniform distribution

5 votes
0 answers
529 views

Analytic variety is a countable union of complex manifolds

5 votes
1 answer
122 views

Extension of a binary operation

5 votes
0 answers
73 views

Functional sequence [duplicate]

5 votes
2 answers
2k views

Jordan block in a matrix with a complex eigenvalue

5 votes
1 answer
306 views

Definite integral, floor function, parameter

5 votes
2 answers
283 views

Berkeley exam summer '79, sequence of continuous functions, integral, convergence

5 votes
1 answer
1k views

Stirling numbers, binomial coefficients

4 votes
5 answers
606 views

$n\times n$ board, non-challenging rooks

4 votes
1 answer
169 views

Polynomial expression of $\frac{\sin x}{x} $

4 votes
1 answer
2k views

Lower limit topology regular space $ T_3$

4 votes
2 answers
2k views

Connected graph, each power of adjacency matrix has zeros

4 votes
0 answers
265 views

$\alpha <1$, series $n^{-\alpha} \sum _{k=1}^n \sin (k^2)$ is bounded

4 votes
1 answer
242 views

Limit of product of $\sin \frac{k}{n}$

4 votes
1 answer
412 views

Quadratic form $\mathbb{R}^n$ homogeneous polynomial degree $2$

4 votes
1 answer
866 views

Additive norm $||a+b||=||a||+||b||$