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Questions tagged [stochastic-calculus]

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Stochastic calculus is a branch of mathematics that operates on stochastic processes. It allows a consistent theory of integration to be defined for integrals of stochastic processes with respect to stochastic processes. It is used to model systems that behave randomly.

4,970 questions 1
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Solution of SDE with exp in integral

Consider the linear stochastic differential equation $$ dX_t = \left[AX_t+K \right]dt + g(t)dW_t, ~~~X_0 =x_0 $$ where $A$ is a $n\times n$ matrix, $K$ is a vector and $W_t$ is a Wiener process. The ... user avatar Sinem
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-1 votes 0 answers 10 views

Solution of two-dimensional SDE in R

How can the solution of a two dimensional stochastic differential equation can be plotted in R? I can use existing functions, I want to plot the exact solution given by applying Itos lemma, not an ... user avatar Sinem
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1 vote 1 answer 18 views

Equivalence of different versions of Markov property

Let $X_t,t\ge 0$ be continuous, $n$-dimensional process and filtration $\mathcal{F}_t=\sigma(X_s,0\le s \le t)$. We want to show the equivalence of the two definition in the following: $$ E[f(X_t)|X_{... user avatar Talking Puppet
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0 votes 0 answers 16 views

Brownian motion and martingale

The following theorem (picture below) is from Peres-Morters book: Brownian motion. Consider an open $O \subset \mathbb{R}^d$ and a harmonic function function $f: \overline{O} \to \mathbb{R}$ such that ... user avatar john
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-1 votes 0 answers 10 views

Determine the solution of the particular Ornstein-Uhlenbeck SDE

Consider the following stochastic differential equation: \begin{equation} dS_t=\mu S_t dt+\sigma dW_t. \end{equation} I tried to solve it by referring to the general Ornstein-Uhlenbeck model, i.e. to \... user avatar AndVld
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0 votes 0 answers 16 views

the proof of existence of solution of stochastic equation

I am going through the proof of the existence of strong solution of SDE on Brownian motion and Stochastic Calculus by Karatzas and Shreve. However, there is a single line I really cannot see how to ... user avatar Zorualyh
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1 vote 0 answers 109 views

Interpreting $\frac{ n^k }{ k! }$ [closed]

So I'm trying to figure out what kind of sense the following formula has: $$\frac{ n^k }{ k! }$$ Does this mean: I choose $k$ Elements from a container of $n$ Elements, where $k$ Elements can be ... user avatar tryg
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2 votes 0 answers 16 views

Does there exist a version of the Burkholder-Davis-Gundy inequality for multidimensional continuous local martingales?

Let $(\Omega,\mathcal{F},\mathbb{F}=(\mathcal{F}_t)_{t \geq 0},\mathbb{P})$ be a stochastic basis and $M$ a continuous local martingale on it with start in $0$. Then the Burkholder-Davis-Gundy ... user avatar Learner
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3 votes 0 answers 31 views

Markov alternative definition

On wiki, there are two definitions on Markov property, which are Let $(\Omega ,{\mathcal {F}},P)$ be a probability space with a filtration $({\mathcal {F}}_{s},\ s\in I)$, for some (totally ordered) ... user avatar Talking Puppet
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3 votes 0 answers 36 views +50

Decompose the Laplace transform of autocorrelation function of a stachastic process using Wiener-Kolmogorov whitening procedure

Here I read that it is possible to use the Wiener-Kolmogorov whitening procedure to decompose the Laplace transform of autocorrelation function into the product of white noise and a system function: $$... user avatar Mark
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2 votes 0 answers 21 views

Question on Markov property

I am self-studying "Introduction to Stochastic Integration" by Hui-Hsiung Kuo and have some doubts on the lemma. In the book it first defines that the Markov property on page 198 as follow ... user avatar Talking Puppet
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1 vote 0 answers 42 views

How to calculate the autocorrelation of Ornstein Uhlenbeck process

Let us consider the following SDE: $$ d x(t)=-\alpha \cdot(x(t)-\mu) \cdot d t+\sqrt{2 \cdot \alpha} \cdot \sigma \cdot d W(t) $$ Its solution is a stationary stochastic process called the Ornstein-... user avatar Mark
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1 vote 0 answers 19 views

Prove that realized variance converges in probability to integrated variance for Ito process

Let $P_{t}$ be a price process of an asset. Assume the log-price $p_{t}=\ln P_{t}$ follows a generalized Ito process $$ d p_{t}=\mu_{t} d t+\sigma_{t} d w_{t}, \quad t \in R, \quad (1) $$ where $\mu_{... user avatar Mark
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3 votes 3 answers 73 views

How can I prove that $\Bbb{P}(X>0)\geq \frac{\Bbb{E}(X)^2}{\Bbb{E}(X^2)}$

I have the following problem: Let $X$ be a nonnegative random variable such that $\Bbb{E}(X^2)<\infty$ Then show that $$\Bbb{P}(X>0)\geq \frac{\Bbb{E}(X)^2}{\Bbb{E}(X^2)}$$ I would like to get ... user avatar Wave
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1 vote 2 answers 30 views

Can I use the Chebychev inequality to prove this statement?

Let $X$ be a random variable with $\Bbb{E}(X^2)<\infty$ and $a>0$ I need to show that $$\Bbb{P}(X>a)\leq \frac{\Bbb{E}(X^2)}{a^2}$$ My idea was the following. Let me first remark that $$\{X&... user avatar Wave
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