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zesy
  • Member for 10 years, 4 months
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14 votes
1 answer
617 views

How to stay productive while you are studying math? [closed]

8 votes
4 answers
2k views

Show rigorously that Pólya urn describes a martingale

8 votes
2 answers
2k views

$\lim_{n \to \infty}f_n(x_n)=f(x)$ if $f_n \to f$ and $x_n \to x$?

8 votes
1 answer
173 views

Question for math purists: is the following proof related to harmonic series wrong?

7 votes
0 answers
199 views

Uniqueness of the transformation turning random variables into IID uniform

7 votes
3 answers
4k views

Why $\sin(x)+\sin(\pi x)$ is not periodic?

6 votes
3 answers
128 views

$(a+2)^3+(b+2)^3+(c+2)^3 \ge 81$ while $a+b+c=3$

6 votes
1 answer
449 views

False proof: Every linear operator (matrix) has an eigenvalue.

5 votes
0 answers
102 views

Conditional expectation (understanding the definition)

5 votes
1 answer
169 views

$ \sum_{n = 1}^{\infty} \frac{1}{n^4}$?

5 votes
0 answers
81 views

$\sum_{n= 0}^{\infty}a_n$ converges, what other series must then also converge?

4 votes
1 answer
193 views

Probability question involving derangements

4 votes
1 answer
137 views

The sequence $(-1)^n\binom{\alpha-1}{n}$ converges.

4 votes
2 answers
2k views

Product of trigonometric polynomials is a trigonometric polynomial

4 votes
1 answer
58 views

Show that certain matrices over rings form a field

3 votes
3 answers
785 views

Prove that $|\log(1 + x^2) - \log(1 + y^2)| \le |x-y|$

3 votes
2 answers
66 views

I need to find $\lim_{h \to 0, h\ne 0} \sqrt[h]{\frac{3^h+2^h}{2}}$

3 votes
2 answers
306 views

Partial fraction decomposition with real polynomials

3 votes
1 answer
99 views

Show that $E[(Y-E[Y|X])*(E[Y|X]-g(X))]=0$

3 votes
0 answers
527 views

Is a limit of a sequence of distribution functions is necessarily a distribution function

3 votes
0 answers
835 views

Central limit theorem with Lyapunov condition

3 votes
1 answer
2k views

Number of permutations where only odd elements must be deranged

3 votes
2 answers
573 views

Finite cover for $[0,1]$

3 votes
2 answers
2k views

If a series converges absolutely, then any sub-series also converges absolutely? [duplicate]

3 votes
3 answers
182 views

Why do we believe that $\sum_{k=1}^{\infty} x_k=\sum_{i=1}^{\infty}\sum_{j=1}^{\infty}x_{ij}$?

2 votes
0 answers
95 views

Proof that $\mathbb E[X]=\sum_{\omega \in \Omega}X(w)P(\{w\})$

2 votes
7 answers
2k views

Meaning of correlation

2 votes
0 answers
480 views

Regularly varying function represented with a slowly varying function

2 votes
2 answers
5k views

How to compute $\sum_{x=0}^{\infty}xa^x$? [duplicate]

2 votes
1 answer
100 views

Why a change of a brownian motion does not depend on the past values of it? [duplicate]

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