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I am a PhD student at UCL


Nov
29
revised Finding an example of a discrete-time strict local martingale.
deleted 47 characters in body; edited title
Nov
29
accepted Finding an example of a discrete-time strict local martingale.
Jul
11
awarded  Yearling
Jun
30
accepted Applying Ito to semi-group of Brownian motion in $\mathbb{R}^d$
Jun
8
awarded  Caucus
May
21
comment Limit of Wiener processes
Thank you, I just copy-pasted the latex.
May
21
comment Limit of Wiener processes
My notes say that Stratonovich would be $$\displaystyle \lim_{n->\infty}\sum_{k=0}^{[2^n t]-1}\big(\frac{W_{(k+1)2^{-n}}+W_{k2^{-n}}}{2}\big)(W_{(k+1)2^{-n}}-W_{k2^{-n}}‌​),$$ what am I missing?
May
21
comment Limit of Wiener processes
Central limit theorem won't help, central limit theorem is for a different type of convergence.
May
20
asked Applying Ito to semi-group of Brownian motion in $\mathbb{R}^d$
May
18
comment Are hitting times of Brownian motion independent?
if $c=\mathbb{P}(T_b<T_a)$, then, by OST, $0=\mathbb{E}[B_{T_a\wedge T_b}]=a(1-c)+bc$. Solve for $c$.
May
18
comment Hitting time of Brownian Motion with a drift
@mike, What is Wald? I have managed to use OST on the exponential martingale and then just differentiate the answer with respect to $b$ to compute the expression 1).
May
18
revised Hitting time of Brownian Motion with a drift
added 99 characters in body
May
18
comment Hitting time of Brownian Motion with a drift
Well OK it's easy to say $T<\infty$ $\mathbb{Q}$-a.s. by the properties of BM, hence it's a.s. finite under $\mathbb{P}$ (absolute continuity). So that is not a problem anymore.
May
18
asked Hitting time of Brownian Motion with a drift
May
17
comment Problem with applying Ito
I have no doubt that this is correct, but could you clarify which version of Ito you are applying? My question was, essentially, how to make it rigorous.
May
17
asked Problem with applying Ito
May
17
comment Find $ P(Z>X+Y)$ where $X,Y,Z \sim U(0,1)$
No, I don't think you understand it properly. The first equality involves indicator function $\mathbb{1}(Z>X+Y)$, which is $1$ on the event $Z>X+Y$ and $0$ on the event $Z\leq X+Y$. Then expectation of such indicator is just the probability of the event $Z>X+Y$, by definition of expectation.
May
17
revised Find $ P(Z>X+Y)$ where $X,Y,Z \sim U(0,1)$
deleted 2 characters in body
May
17
answered Find $ P(Z>X+Y)$ where $X,Y,Z \sim U(0,1)$
May
17
asked Polarisation in proving Kunita-Watanabe identinty