User Yaroslav Bulatov - Mathematics Stack Exchange

Yaroslav Bulatov

Member for 13 years, 4 months
Last seen this week

Twitter
GitHub
medium.com/@yaroslavvb
San Francisco, CA, United States

207 Questions

Score Activity Newest Views

69 votes

5 answers

46k views

Matrices commute if and only if they share a common basis of eigenvectors?

asked Oct 7, 2010 at 8:16

13 votes

1 answer

910 views

Proving $\sqrt{1-x^2}\ge \operatorname{erf}(\sqrt{-\log x})$

asked Oct 14, 2010 at 22:43

13 votes

2 answers

293 views

Inverse of integral transform $f(s)=\int_0^\infty g(x) \exp(-s g(x)) \mathbb{d}x$

asked Sep 5, 2021 at 15:07

12 votes

3 answers

567 views

Average value of $\frac{x'A^2x}{x'A^3x}$ over surface of $n$-dimensional sphere

asked Aug 19, 2021 at 15:37

9 votes

3 answers

493 views

Behavior of inverse of $f(s)=\frac{1}{H_n}\sum_{i=1}^n \left(1-\frac{1}{i}\right)^s\frac{1}{i}$

asked Jun 22, 2021 at 19:19

9 votes

1 answer

186 views

What is $E[1/\|x\|^4]$ where $x\sim$ Gaussian($0,C\cdot $diag($1,1/2,1/3,1/4,\ldots$))?

asked Oct 13, 2022 at 0:32

9 votes

3 answers

2k views

Proving $1-\exp(-4x^2/ \pi) \ge \text{erf}(x)^2$

asked Oct 15, 2010 at 22:00

9 votes

3 answers

2k views

Implementing trig functions for dual numbers

asked Aug 16, 2014 at 22:39

8 votes

3 answers

898 views

Limit of Gamma integrals

asked Sep 18, 2010 at 6:41

7 votes

1 answer

3k views

Second order approximation of $\log \det X$

asked Nov 29, 2012 at 5:07

7 votes

1 answer

464 views

Solving $\frac{\partial}{\partial t} f =hf+ h \int \mathrm {d} i\, h f$

asked Apr 25 at 19:20

7 votes

2 answers

263 views

Frobenius norm of a product of Gaussian matrices

asked Nov 25 at 0:04

7 votes

2 answers

232 views

Showing $E\operatorname{Tr}(AAA^TA^T)=n^3 + 2n$

asked Dec 1 at 20:37

6 votes

1 answer

851 views

Getting generators of graphs automorphism group

asked Mar 3, 2011 at 2:36

6 votes

1 answer

5k views

Meaning of Lagrange multiplier always being 0?

asked Aug 10, 2010 at 2:34

6 votes

3 answers

2k views

discrete version of Laplacian

asked Oct 8, 2010 at 16:53

6 votes

1 answer

240 views

Showing that $\cos(u_1,u_3)=\cos(u_1,u_2)\cos(u_2,u_3)$ for nearby $u_i$

asked Sep 7, 2022 at 21:53

6 votes

0 answers

318 views

Estimate nearly-singular Gaussian covariance matrix

asked Jun 10, 2021 at 18:22

5 votes

4 answers

172 views

Behavior of $\sum_i^n (1-\frac{1}{i})^s$ as a function of $s$?

asked Jun 17, 2021 at 5:06

5 votes

2 answers

125 views

Is this function bounded? $g(n)=t>1\text{ s.t. } \int_1^n (1-i^{-p})^t i^{-p} \, di =\varepsilon$

asked Jun 25, 2021 at 22:50

5 votes

1 answer

168 views

Conditions for $I-x A$ to be a convergent matrix for some $x\in \mathbb{R}$

asked Jul 9, 2022 at 20:16

5 votes

0 answers

92 views

Sampling from intersection of sphere and simplex

asked Sep 18, 2022 at 3:59

5 votes

1 answer

108 views

Minimizing $\frac{\operatorname{Tr}(H^2)^2}{\operatorname{Tr}(H^3)\operatorname{Tr}H}$

asked Mar 1 at 2:39

5 votes

2 answers

149 views

Minimizing $\frac{\|p\|_2^2}{\|p\|_\infty}$ for probability vector $p$

asked Mar 5 at 6:49

5 votes

3 answers

509 views

Number of classes of k-digit strings when digit order and identity doesn't matter

asked Oct 19, 2010 at 22:37

5 votes

2 answers

681 views

normalization factor for restricted density

asked Sep 5, 2010 at 23:51

5 votes

3 answers

2k views

Diagonal of an inverse of a sparse matrix

asked Jan 22, 2011 at 2:38

5 votes

3 answers

3k views

Optimal symmetric rank-1 approximation

asked Jan 7, 2013 at 4:22

5 votes

3 answers

271 views

Computing $(A\otimes I + I \otimes A)^{-1} \text{vec}B$

asked Aug 19, 2019 at 21:56

5 votes

2 answers

126 views

Least squares solution to underdetermined Lyapunov equation

asked Nov 16 at 19:00

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