-2
$\begingroup$

I couldn't find the answer in literature so any idea would be helpful.

$\endgroup$
2
  • $\begingroup$ This should actually have been posted to math.stackexchange.com instead as it is not research level. I've voted to migrate it there. $\endgroup$ Commented Apr 25, 2020 at 17:48
  • $\begingroup$ (I forgot which site I was on - I wouldn't have answered the question if I had noticed it was on MathOverflow.) $\endgroup$ Commented Apr 25, 2020 at 17:49

1 Answer 1

1
$\begingroup$

Not in general. The standard counterexample is to let $U \sim U(0,1)$, $X_n = n 1_{\{U \le 1/n\}}$, and $X=0$.

There are several basic theorems giving sufficient conditions for this to hold, e.g. monotone convergence, dominated convergence, uniform integrability. They can be found in any graduate-level probability textbook.

$\endgroup$
2
  • $\begingroup$ Thank you for the notice. What I am working on concretely are variables in form of e^tXiY, where t is a real number, and Xi, Yj are independent sequences of random variables having binomial distribution. How to figure out would the condition hold in this case? $\endgroup$ Commented Apr 25, 2020 at 16:11
  • $\begingroup$ Maybe look in the literature for results on sufficient conditions, as the answer suggests... $\endgroup$
    – R.P.
    Commented Apr 25, 2020 at 17:01

Not the answer you're looking for? Browse other questions tagged .