Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options not deleted user 113397

Theory and applications of probability and stochastic processes: e.g. central limit theorems, large deviations, stochastic differential equations, models from statistical mechanics, queuing theory.

11 votes

Find the area of the region enclosed by $\frac{\sin x}{\sin y}=\frac{\sin x+\sin y}{\sin(x+y...

An approach bypassing polylogarithms is as follows: \begin{align}\int_1^{1+\sqrt2}\log\frac{t+1}{t(t-1)}\frac{dt}t&\stackrel{ibp}=\int_1^{1+\sqrt2}\frac{t^2+2t-1}{t(t^2-1)}\log t\,dt\\&\stackrel{t=e^u …
TheSimpliFire's user avatar
0 votes
1 answer
156 views

Analogues of Kac-Bernstein characterisation theorem for non-normal distributions

Let $X,Y$ be two independent random variables. The Kac-Bernstein theorem states that if $X+Y,X-Y$ are also independent, then $X,Y$ are Normal. Are there analogues of this theorem for non-normal, conti …
TheSimpliFire's user avatar
8 votes
3 answers
585 views

Jensen-like inequality for random matrix: $\Bbb E[\det X^2]\ge\det\Bbb E[X^2]$

Let $X\in M_n(\Bbb R)$ be a random matrix with iid elements following a continuous distribution. What are the necessary and sufficient conditions for $$\Bbb E[\det X^2]\ge\det\Bbb E[X^2]$$ to hold? Is …
TheSimpliFire's user avatar
10 votes
Accepted

Jensen-like inequality for random matrix: $\Bbb E[\det X^2]\ge\det\Bbb E[X^2]$

From the identities in @OlivierBégassat's answer, the inequality $\Bbb E\det X^2\ge\det\Bbb EX^2$ can be written as $$\small n!\sum_{f=0}^n\binom nf(-1)^{n-f-1}(n-f-1)(\Bbb V[X]+\Bbb E[X]^2)^f\Bbb E[X …
TheSimpliFire's user avatar
0 votes

A function with unexpectedly simple Legendre transformation

Claim. $J(x)=\tfrac12x^2+\ln|x|+c$ for $|x|>1$ with $c$ constant. Proof: Here, an explicit form for $I(x)$ is not needed but I can't use it to prove $c=0$. For $|x|>1$, the substitution $y=2\cos t$ fo …
TheSimpliFire's user avatar