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Feb 20, 2023 at 19:46 comment added Thomas Kojar then i suggest making a new question and we will try to help.
Feb 20, 2023 at 10:57 comment added Fawen90 @ThomasKojar Thanks. The answer seems to be highly relevant to my question, while the reasoning is not 100% clear to me...
Feb 20, 2023 at 6:15 comment added Thomas Kojar If your setting is more tricky or different, I would suggest making a new question about this.
Feb 20, 2023 at 6:10 comment added Thomas Kojar that is a more doable question and you don't need a common Brownian motion for that. See second answer there: mathoverflow.net/questions/405610/a-comparison-of-diffusions/…
Feb 19, 2023 at 7:44 comment added Fawen90 @mike Fortunately I don't care about the joint law of $(X,Y)$. I only need that, after changing a suitable probability space, $Y$ is "later" than $X$. The motivation is that I wish to show the exit time of $(-1,1)$ for $X$ is "smaller" than that of $Y$. So I do want this answer, but I don't quit follow your construction...
Feb 19, 2023 at 6:50 comment added mike I really think you don't want this answer. Thie biggest thing wrong with it is that it ignores the joint distribution of the 2 processes, and while your question does not ask for the same joint distribution, I think you must want it. Consider the case of $\alpha, \beta$ 2 different constants, so $X,Y$ are just $\alpha W_t, \beta W_t$. What do you want done with them ?
Feb 18, 2023 at 12:14 comment added Fawen90 @mike Thank you mike for the answer, while it is not completely clear to me. Do you mind detailing this embedding procedure by providing an answer? I do appreciate
Feb 18, 2023 at 7:32 comment added mike You can do this up to any finite time T, but it is a cheat. Just imbed the first process, the wait for the brown Ian motion to return to zero, and imbed the second, even using a different Brownian motion if you like. Of course, you could them in either order.
Feb 18, 2023 at 2:15 history edited LSpice CC BY-SA 4.0
`\DeclareMathOperator`
Feb 17, 2023 at 23:08 comment added Thomas Kojar If there was a common Brownian motion, it would be need to be adaptable to two different filtrations and thus, for example, contradict the Markov property.
Feb 17, 2023 at 23:07 comment added Thomas Kojar In the DS theorem, the two Brownian motions constructed are adapted to different filtrations.
Feb 17, 2023 at 16:24 comment added Fawen90 @IosifPinelis Yes. I think "taking values in $\mathbb R_+$" means that $\alpha_t\ge 0$ (if my English is not that bad :))
Feb 17, 2023 at 15:56 history asked Fawen90 CC BY-SA 4.0