Sign up ×
Mathematics Stack Exchange is a question and answer site for people studying math at any level and professionals in related fields. It's 100% free, no registration required.

Let $B_t$ be a Brownian motion process. Let $$O_t = e^{-\alpha t} \int^t_0 e^{\alpha s} dB_s$$ Find $\mathsf{E}[O_t]$ and show that $O_t$ is a Gaussian process.

I think $\mathsf{E}[O_t]=e^{-\alpha t} \mathsf{E}\left[ \int^t_0 e^{\alpha s} dB_s\right] = e^{-\alpha t} \times 0 = 0$ as the Ito integral is a martingale with expectation $0$ by definition. But I am not sure why it is a martingale in the first place...
No idea how to show it's a Gaussian process.

Please help!

share|cite|improve this question
What would be suitable indications really depends on what you know about Brownian motion and Gaussian processes--a point about which you say nothing in your post. – Did Oct 3 '12 at 5:35
In fact, this Ito integral is for deterministic integrand, hence it coincides with ... .... and by the properties of jointly Gaussian r.v. one gets that $O_t$ is ... ... – Tarasenya Oct 3 '12 at 7:30

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Browse other questions tagged or ask your own question.