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8 votes
2 answers
1k views

The Wiener measure of an open set

There is so much written about the Brownian motion and I suspect the answers to the questions below are hidden in somewhere in the literature but I cannot find them Denote by $E$ the Banach space ...
Liviu Nicolaescu's user avatar
5 votes
2 answers
688 views

Endpoint of Brownian motion conditional on high maxima

Note: This question is closely related to an earlier question: A large noise limit. Let $W$ be a standard one dimensional Brownian motion. For every $\varepsilon > 0$, let $A_\varepsilon$ denote ...
Nate River's user avatar
  • 6,215
7 votes
2 answers
984 views

Brownian motion in $n$ dimensions

Consider a particle starting at the origin in $\mathbb{R}^n$ and undergoing Brownian motion. Is there an expression known for the probability of the particle hitting the sphere $S^{n - 1}_r = \{x \in \...
user82390's user avatar
7 votes
2 answers
613 views

Fractional Brownian motion of Riemann-Liouville type is not a semimartingale

Given a filtered probability space $(\Omega,\mathcal{F},\mathbb{F},\mathbb{P})$ satisfying the usual conditions, $B$ a standard one-dimensional Brownian motion and $H\in(0,1/2)$. Consider the process $...
El_mago's user avatar
  • 199
5 votes
1 answer
523 views

Scaling of First-passage times for Random Walk on integer lattices

Consider simple symmetric random walk $S_{n} = (S_{n}^{(1)},\dots, S_{n}^{(d)})$ on the d-dimensional integer lattice with starting point the origin. Let $\tau_{N}$ be the first time $S_{n}$ exits ...
John Lotos's user avatar
5 votes
1 answer
284 views

Malliavin derivative of stopped Brownian motion

Cross-posted from: "https://math.stackexchange.com/questions/3917971/malliavin-derivative-of-stopped-brownian-motion" I have a small question concerning the Malliavin derivatives. It could ...
Cain's user avatar
  • 393
4 votes
1 answer
447 views

Area enclosed by Brownian motion (without winding number)

The question Average Value of Area Closed by Brownian Motion turned out to be about the Lévy area process, which measures "signed area with multiplicity" enclosed by Brownian motion (e.g. each ...
Nate Eldredge's user avatar
3 votes
1 answer
655 views

Forgery theorem: the Brownian motion stays close to any curve with positive probability

In a paper I am reading the authors claim that, if $B$ is a standard BM in $\mathbb{R}$ and $f\in C([0,1],\mathbb{R})$, then for any $\epsilon>0$ $$ \mathbb{P}(\sup_{t\in [0,1]}|B_t-f(t)|<\...
No-one's user avatar
  • 1,149
3 votes
1 answer
233 views

Brownian level sets and continuous functions

Let $V_t$ and $W_t$ be independent standard Wiener processes ($t\ge 0$, $W_t,V_t\in\mathbb R$). Let $C$ be the event that there is a continuous function $f$ such that for all $s$, $t$, $$ W_t=W_s\iff ...
Bjørn Kjos-Hanssen's user avatar
1 vote
0 answers
99 views

Expectation of $B_u \operatorname{argmax}_t B_t$

This question is a repost from math.stackexchange. The question turned out to be harder than I initially thought, so I decided to try my luck here. Yesterday I asked a question about the joint law of ...
tsnao's user avatar
  • 620
1 vote
1 answer
141 views

Differentiable approximation of Brownian diffusion with bounded volatility

Let $\{W_t\}_{t\in[0;T]}$ be a one-dimensional Brownian motion and let $\{\mathcal F_t\}_{t\in[0;T]}$ be the augmented filtration generated by this Brownian motion. Let $\{\sigma_t\}_{t\in[0;T]}$ be ...
Kolodez's user avatar
  • 335
0 votes
1 answer
183 views

Probability to cross dynamic boundary for 1D-random walk?

context: Imagine we have an evolving bit sequence (ex: 001011...) where the probability to get 0 or 1 is 1/2. n is the lengh of my sequence (the number of bits) I can make an analogy with random walk: ...
Jonathan's user avatar
0 votes
2 answers
6k views

Quadratic covariation of two not independent Brownian motions

Given two not independent Brownian motions, $X$ and $Y$. I was wondering if we can say anything about the quadratic covariation of $X$ and $Y$, $\langle X,Y \rangle_t$. I know that for two independent ...
Charlie Shuffler's user avatar