Ilya

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Name Ilya
Member for 2 years
Seen May 17 at 14:28
Website
Location Leiden
Age 25
I am PhD student at TU Delft.
Apr
4
comment Time integral of a diffusion
[Cross-posted](math.stackexchange.com/questions/350837/…)
Mar
29
comment Nontrivial lower bounds on Cheeger inequalities for Markov chains
The book by Meyn and Tweedie "Markov Chains and Stochastic Stability" discusses many criteria for the convergence of $\lim_n\|\mu K^n - \pi\|$. Since this difference can be regarded as a size of $K^n$ on functions orthogonal to $\pi$, I guess shall help you as well.
Mar
28
comment stopping time expectation for gambler’s ruin
@Douglas: completely agree, but since OP asked how to find a moment using MGT, I thought it's worth reminding how to do this.
Mar
20
comment stopping time expectation for gambler’s ruin
In case you know moment-generating function of $\tau$, you can simply use the fact that $$ \mathsf E[\tau^2] = m''(0) $$ where $m(t) = \mathsf E[\mathrm e^{\tau t}]$ is MGT of $\tau$
Mar
15
awarded  Yearling
Mar
15
awarded  Yearling
Mar
15
revised Maximal probability of “infinitely often” over MDP
added 358 characters in body
Mar
15
comment Equivalence of two definitions of Lyapunov exponents
Another website: math.stackexchange.com is perhaps more suitable for such questions
Mar
15
comment The property of a Markov measure
I would support HW in his question about the framework (even though it perhaps not related to probability) - seems to be similar to what I am doing.
Mar
15
comment The property of a Markov measure
By a Markov measure you mean, that for some stochastic kernel $K$ on the measurable space $(A,2^A)$ it holds that $P$ is the induced measure on $A^\Bbb N$?
Mar
15
asked Maximal probability of “infinitely often” over MDP
Mar
15
comment The property of a Markov measure
What does an open set men in your context?
Mar
14
comment How identify bounded Borel measurable functions
Do you mean $\langle f,\mu\rangle := \int_S f(x)\mu(\mathrm dx)$ for any $\mu \in M(S)$ and bounded Borel $f$?
Mar
14
comment Application of Stochastic Calculus
I would suggest to take a look at the 1st chapter of "Stochastic Differential Equations: at introduction with applications" by B. Oksendal to start being awared of (a subset of) possible applications.
Mar
14
revised Sufficiency of stationary policy for negative stochastic dynamic programming
added 71 characters in body; edited title
Mar
14
asked Sufficiency of stationary policy for negative stochastic dynamic programming
Mar
5
comment Expected distance of a random point to the convex hull of N other points
Do you assume a fixed probability space (=dependence structure between $X$ and $Y$), or you only know distributions?
Feb
21
comment Distribution of maximum of random walk conditioned to stay positive
There is a way to solve this problem even for more general Markov processes, but could you please tell me more precise about your conditioning. In your case $\mathsf P(Y_k\geq 0\;\forall k) = 0$ so I guess you are interested rather in $$ \mathsf P(M_n \geq m|Y_k\geq 0 \; \forall 0\leq k\leq n) $$ am I right?
Feb
19
accepted approximation methods in integral equations
Feb
18
comment approximation methods in integral equations
@rafiki: you are welcome
Feb
18
answered approximation methods in integral equations
Feb
14
accepted Upper bound concerning Snell envelope
Feb
14
comment Upper bound concerning Snell envelope
@Paul: I'm not sure whether it's true. Let $X\equiv \frac 12$ and let $p = 2$, then LHS is $\frac14$ and RHS is $\frac1{16}$, so your philosophy does not apply at least in such case.
Feb
14
comment Upper bound concerning Snell envelope
@Paul: are you sure you have to take $p$ power in the RHS two times? Or you are just asking the question in the math.stackexchange version?
Feb
14
comment A terminal coalgebra of a certain functor on Mes
Thanks, I'll take a look.
Feb
14
answered Upper bound concerning Snell envelope
Feb
14
asked A terminal coalgebra of a certain functor on Mes
Jan
21
comment Coupling of vectors
@Anthony: I agree - and I am pretty sure that one come up with a maximal coupling of $P$ and $\hat P$ doing it sequentially - I just wondered whether it's possible for the maximal coupling which satisfies one more additional assumption (aka $\gamma$-coupling according to Lindvall).
Jan
20
comment Coupling of vectors
As far as I've checked your example, it is correct - thanks again. I guess, I shall accept you answer - but could you suggest how to compute $\Bbb P(X_1 = \hat X_1)$ or maybe you know how to express $\Bbb P(X\in A,\hat X\in \hat A)$?
Jan
20
comment Coupling of vectors
Thanks a lot for this reference!
Jan
19
asked Uniform transience criteria
Jan
19
comment Coupling of vectors
Thank you. Do you have a reference for the proof of the last formula? It's like a Fubini theorem, but I've never seen a proof of its version for kernels. Also, in your first example, do you mean that $P$ and $\hat P$ in place of $\mu$ and $\hat \mu$ - just to keep it consistent with the notation in OP?
Jan
19
comment Coupling of vectors
@Colin: thanks, fixed
Jan
19
revised Coupling of vectors
edited body
Jan
19
comment Tails of sums of Weibull random variables
I guess, the following reference may be useful for you, it's also pretty recent: [An Introduction to Heavy-Tailed and Subexponential Distributions, 2011](springer.com/mathematics/probability/book/…). Perhaps, available in Russian as well. Furthermore, [this paper](math.nsc.ru/LBRT/v1/dima/publications/…) provides untight rates of convergence which hold however even in case you only have first two moments
Jan
18
revised Coupling of vectors
added 403 characters in body
Jan
18
asked Coupling of vectors
Jan
18
revised Approximating a hitting time for some state using the stationary distribution?
deleted 2 characters in body
Jan
18
comment Approximating a hitting time for some state using the stationary distribution?
@Ori: thanks ${{}}$
Jan
17
comment a problem on DTMC
It shall give you hint where to look at. You are dealing exactly with the concept of "taboo" probabilities, which are defined as $$ _rP^n(i,j):=\mathsf P_i(X_n = j,\tau_r>n) $$ where $\tau_r$ is the first hitting time of the state $r$. It is known that $_rP^n(i,j)$ is a sub-markovian kernel in case $r$ is accesible from some other states, but as you are doing conditioning, the kernels you are considering are indeed markovian kernels. I would suggest that you read about them in [Meyn and Tweedie](probability.ca/MT/BOOK.pdf). Just look for "taboo probabilit
Jan
17
answered Approximating a hitting time for some state using the stationary distribution?
Jan
17
awarded  Organizer
Jan
17
comment Convergence rate for product of stochastic matrices
Number of iterations until $x(t)$ converges to a stable point - don't you mean that it shall reach such point in a finite number of steps?
Jan
17
revised Integral Fredholm equation of the second type
added 25 characters in body
Jan
17
comment Change of measure Markov process
Took me quite some time to get it. Thanks (a bit too late, though) anyway!
Jan
11
comment Topological conditions of Kolmogorov Extension Theorem
Thanks a lot, Michael! Will you consider also putting this answer on a linked MSE question?
Jan
11
asked Topological conditions of Kolmogorov Extension Theorem
Nov
30
comment Is positive part of the kernel measurable?
@Michael: thanks for the comment
Nov
30
comment Symmetries of probability distributions
@Colin: thank you very much, I shall check that