Skip to main content
replaced http://mathoverflow.net/ with https://mathoverflow.net/
Source Link

This is a follow-up to my previous question on MathOverflowprevious question on MathOverflow.

Is there a way to combine the Dambis-Dubins-Schwarz theorem and the Martingale Representation Theorem to get the following result?

Let $(M_t, t\ge 0)$ be a continuous $(\mathcal{F}_t)_{t \ge0}$ local martingale, then there exists some Brownian motion $B$ and some progressively measurable process $\xi$ on some probability space such that $$M_t = \int_0^t \xi_s dB_s = \large{ B_{\int_0^t \xi_s^2 ds}} \quad \forall t \in [0,\infty)$$

In particular it would follow that $\langle M \rangle_t=\int_0^t \xi_s^2 ds$ (by Ito's Isometry?).

This is a follow-up to my previous question on MathOverflow.

Is there a way to combine the Dambis-Dubins-Schwarz theorem and the Martingale Representation Theorem to get the following result?

Let $(M_t, t\ge 0)$ be a continuous $(\mathcal{F}_t)_{t \ge0}$ local martingale, then there exists some Brownian motion $B$ and some progressively measurable process $\xi$ on some probability space such that $$M_t = \int_0^t \xi_s dB_s = \large{ B_{\int_0^t \xi_s^2 ds}} \quad \forall t \in [0,\infty)$$

In particular it would follow that $\langle M \rangle_t=\int_0^t \xi_s^2 ds$ (by Ito's Isometry?).

This is a follow-up to my previous question on MathOverflow.

Is there a way to combine the Dambis-Dubins-Schwarz theorem and the Martingale Representation Theorem to get the following result?

Let $(M_t, t\ge 0)$ be a continuous $(\mathcal{F}_t)_{t \ge0}$ local martingale, then there exists some Brownian motion $B$ and some progressively measurable process $\xi$ on some probability space such that $$M_t = \int_0^t \xi_s dB_s = \large{ B_{\int_0^t \xi_s^2 ds}} \quad \forall t \in [0,\infty)$$

In particular it would follow that $\langle M \rangle_t=\int_0^t \xi_s^2 ds$ (by Ito's Isometry?).

Notice removed Improve details by CommunityBot
Bounty Ended with no winning answer by CommunityBot
Notice added Improve details by Chill2Macht
Bounty Started worth 100 reputation by Chill2Macht
added 29 characters in body
Source Link
Chill2Macht
  • 6.5k
  • 5
  • 30
  • 62

This is a follow-up to my previous question on MathOverflow.

Is there a way to combine the Dambis-Dubins-Schwarz theorem and the Martingale Representation Theorem to get the following result?

Let $X$$(M_t, t\ge 0)$ be a continuous $(\mathcal{F}_t)_{t \ge0}$ local martingale (under the natural filtration), then there exists some Brownian motion $B$ and some progressively measurable process $\xi$ on some probability space such that $$X_t = \int_0^t \xi_s dB_s = \large{ B_{\int_0^t \xi_s^2 ds}} \quad \forall t \in [0,\infty)$$$$M_t = \int_0^t \xi_s dB_s = \large{ B_{\int_0^t \xi_s^2 ds}} \quad \forall t \in [0,\infty)$$

In particular it would follow that $\langle X \rangle_t=\int_0^t \xi_s^2 ds$$\langle M \rangle_t=\int_0^t \xi_s^2 ds$ (by Ito's Isometry?).

This is a follow-up to my previous question on MathOverflow.

Is there a way to combine the Dambis-Dubins-Schwarz theorem and the Martingale Representation Theorem to get the following result?

Let $X$ be a continuous local martingale (under the natural filtration), then there exists some Brownian motion $B$ and some progressively measurable process $\xi$ on some probability space such that $$X_t = \int_0^t \xi_s dB_s = \large{ B_{\int_0^t \xi_s^2 ds}} \quad \forall t \in [0,\infty)$$

In particular it would follow that $\langle X \rangle_t=\int_0^t \xi_s^2 ds$.

This is a follow-up to my previous question on MathOverflow.

Is there a way to combine the Dambis-Dubins-Schwarz theorem and the Martingale Representation Theorem to get the following result?

Let $(M_t, t\ge 0)$ be a continuous $(\mathcal{F}_t)_{t \ge0}$ local martingale, then there exists some Brownian motion $B$ and some progressively measurable process $\xi$ on some probability space such that $$M_t = \int_0^t \xi_s dB_s = \large{ B_{\int_0^t \xi_s^2 ds}} \quad \forall t \in [0,\infty)$$

In particular it would follow that $\langle M \rangle_t=\int_0^t \xi_s^2 ds$ (by Ito's Isometry?).

Source Link
Chill2Macht
  • 6.5k
  • 5
  • 30
  • 62

How to Simplify the Representation of Local Martingales?

This is a follow-up to my previous question on MathOverflow.

Is there a way to combine the Dambis-Dubins-Schwarz theorem and the Martingale Representation Theorem to get the following result?

Let $X$ be a continuous local martingale (under the natural filtration), then there exists some Brownian motion $B$ and some progressively measurable process $\xi$ on some probability space such that $$X_t = \int_0^t \xi_s dB_s = \large{ B_{\int_0^t \xi_s^2 ds}} \quad \forall t \in [0,\infty)$$

In particular it would follow that $\langle X \rangle_t=\int_0^t \xi_s^2 ds$.