convergence in law of an exponential brownian motion

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I have a queston about the convergence in law of the following stochastic processe:



$$leftI_t=left(int_0^te^B_sdsright)^1/sqrttright_tgeq 0$$



with $B_t_tgeq 0$ is a standrad brownian motion.



Prove that $I_trightarrow e^$ in law, where $N$ has the gaussian distribution $N(0,1)$.



I have tried by scaling property of brownian motion, but it does not work. I try also with the Laplace tranformation, but it is really difficult to discrible $I_t$'s transformation. Does someone have an idea? Thanks a lot!










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    @ Higgs88 : You should think about Laplace Method (the one that talk about $L^P$ convergence when $ptoinfty$ of a suitable random variable (or measurable function), by the way scaling property is clearly a step in the process. Best regards
    – TheBridge
    Oct 13 '12 at 21:30














up vote
2
down vote

favorite












I have a queston about the convergence in law of the following stochastic processe:



$$leftI_t=left(int_0^te^B_sdsright)^1/sqrttright_tgeq 0$$



with $B_t_tgeq 0$ is a standrad brownian motion.



Prove that $I_trightarrow e^$ in law, where $N$ has the gaussian distribution $N(0,1)$.



I have tried by scaling property of brownian motion, but it does not work. I try also with the Laplace tranformation, but it is really difficult to discrible $I_t$'s transformation. Does someone have an idea? Thanks a lot!










share|cite|improve this question



















  • 1




    @ Higgs88 : You should think about Laplace Method (the one that talk about $L^P$ convergence when $ptoinfty$ of a suitable random variable (or measurable function), by the way scaling property is clearly a step in the process. Best regards
    – TheBridge
    Oct 13 '12 at 21:30












up vote
2
down vote

favorite









up vote
2
down vote

favorite











I have a queston about the convergence in law of the following stochastic processe:



$$leftI_t=left(int_0^te^B_sdsright)^1/sqrttright_tgeq 0$$



with $B_t_tgeq 0$ is a standrad brownian motion.



Prove that $I_trightarrow e^$ in law, where $N$ has the gaussian distribution $N(0,1)$.



I have tried by scaling property of brownian motion, but it does not work. I try also with the Laplace tranformation, but it is really difficult to discrible $I_t$'s transformation. Does someone have an idea? Thanks a lot!










share|cite|improve this question















I have a queston about the convergence in law of the following stochastic processe:



$$leftI_t=left(int_0^te^B_sdsright)^1/sqrttright_tgeq 0$$



with $B_t_tgeq 0$ is a standrad brownian motion.



Prove that $I_trightarrow e^$ in law, where $N$ has the gaussian distribution $N(0,1)$.



I have tried by scaling property of brownian motion, but it does not work. I try also with the Laplace tranformation, but it is really difficult to discrible $I_t$'s transformation. Does someone have an idea? Thanks a lot!







stochastic-processes






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edited Oct 12 '12 at 17:27









MJD

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asked Oct 12 '12 at 17:21









Higgs88

422212




422212







  • 1




    @ Higgs88 : You should think about Laplace Method (the one that talk about $L^P$ convergence when $ptoinfty$ of a suitable random variable (or measurable function), by the way scaling property is clearly a step in the process. Best regards
    – TheBridge
    Oct 13 '12 at 21:30












  • 1




    @ Higgs88 : You should think about Laplace Method (the one that talk about $L^P$ convergence when $ptoinfty$ of a suitable random variable (or measurable function), by the way scaling property is clearly a step in the process. Best regards
    – TheBridge
    Oct 13 '12 at 21:30







1




1




@ Higgs88 : You should think about Laplace Method (the one that talk about $L^P$ convergence when $ptoinfty$ of a suitable random variable (or measurable function), by the way scaling property is clearly a step in the process. Best regards
– TheBridge
Oct 13 '12 at 21:30




@ Higgs88 : You should think about Laplace Method (the one that talk about $L^P$ convergence when $ptoinfty$ of a suitable random variable (or measurable function), by the way scaling property is clearly a step in the process. Best regards
– TheBridge
Oct 13 '12 at 21:30










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This is an answer based on the comment given by TheBridge above.



Basically we note by the scaling property that $(B_s)_sin[0,t] stackreld= t^1/2 (B_s/t)_s in [0,t]$. Therefore $$int_0^t e^B_sds stackreld= int_0^t e^t^1/2 B_s/tds = tint_0^1 e^t^1/2B_udu,$$ where we make a change of variable $s=tu$ in the final equality. Now using the fact that $L^p$ norms converge to the $L^infty$ norm as $p to infty$, and setting $p = sqrt t$ we see that $$lim_t to infty bigg(tint_0^1 e^t^1/2B_udu bigg)^1/sqrtt = 1 cdot e^max_t in [0,1] B_t.$$ We used the fact that $t^1/sqrtt to 1$.



But (see Revuz & Yor Chapter 3) it is well known that $max_[0,1] B_t stackreld= |N|$ where $N sim N(0,1)$. This completes the proof.






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    This is an answer based on the comment given by TheBridge above.



    Basically we note by the scaling property that $(B_s)_sin[0,t] stackreld= t^1/2 (B_s/t)_s in [0,t]$. Therefore $$int_0^t e^B_sds stackreld= int_0^t e^t^1/2 B_s/tds = tint_0^1 e^t^1/2B_udu,$$ where we make a change of variable $s=tu$ in the final equality. Now using the fact that $L^p$ norms converge to the $L^infty$ norm as $p to infty$, and setting $p = sqrt t$ we see that $$lim_t to infty bigg(tint_0^1 e^t^1/2B_udu bigg)^1/sqrtt = 1 cdot e^max_t in [0,1] B_t.$$ We used the fact that $t^1/sqrtt to 1$.



    But (see Revuz & Yor Chapter 3) it is well known that $max_[0,1] B_t stackreld= |N|$ where $N sim N(0,1)$. This completes the proof.






    share|cite|improve this answer
























      up vote
      0
      down vote













      This is an answer based on the comment given by TheBridge above.



      Basically we note by the scaling property that $(B_s)_sin[0,t] stackreld= t^1/2 (B_s/t)_s in [0,t]$. Therefore $$int_0^t e^B_sds stackreld= int_0^t e^t^1/2 B_s/tds = tint_0^1 e^t^1/2B_udu,$$ where we make a change of variable $s=tu$ in the final equality. Now using the fact that $L^p$ norms converge to the $L^infty$ norm as $p to infty$, and setting $p = sqrt t$ we see that $$lim_t to infty bigg(tint_0^1 e^t^1/2B_udu bigg)^1/sqrtt = 1 cdot e^max_t in [0,1] B_t.$$ We used the fact that $t^1/sqrtt to 1$.



      But (see Revuz & Yor Chapter 3) it is well known that $max_[0,1] B_t stackreld= |N|$ where $N sim N(0,1)$. This completes the proof.






      share|cite|improve this answer






















        up vote
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        down vote










        up vote
        0
        down vote









        This is an answer based on the comment given by TheBridge above.



        Basically we note by the scaling property that $(B_s)_sin[0,t] stackreld= t^1/2 (B_s/t)_s in [0,t]$. Therefore $$int_0^t e^B_sds stackreld= int_0^t e^t^1/2 B_s/tds = tint_0^1 e^t^1/2B_udu,$$ where we make a change of variable $s=tu$ in the final equality. Now using the fact that $L^p$ norms converge to the $L^infty$ norm as $p to infty$, and setting $p = sqrt t$ we see that $$lim_t to infty bigg(tint_0^1 e^t^1/2B_udu bigg)^1/sqrtt = 1 cdot e^max_t in [0,1] B_t.$$ We used the fact that $t^1/sqrtt to 1$.



        But (see Revuz & Yor Chapter 3) it is well known that $max_[0,1] B_t stackreld= |N|$ where $N sim N(0,1)$. This completes the proof.






        share|cite|improve this answer












        This is an answer based on the comment given by TheBridge above.



        Basically we note by the scaling property that $(B_s)_sin[0,t] stackreld= t^1/2 (B_s/t)_s in [0,t]$. Therefore $$int_0^t e^B_sds stackreld= int_0^t e^t^1/2 B_s/tds = tint_0^1 e^t^1/2B_udu,$$ where we make a change of variable $s=tu$ in the final equality. Now using the fact that $L^p$ norms converge to the $L^infty$ norm as $p to infty$, and setting $p = sqrt t$ we see that $$lim_t to infty bigg(tint_0^1 e^t^1/2B_udu bigg)^1/sqrtt = 1 cdot e^max_t in [0,1] B_t.$$ We used the fact that $t^1/sqrtt to 1$.



        But (see Revuz & Yor Chapter 3) it is well known that $max_[0,1] B_t stackreld= |N|$ where $N sim N(0,1)$. This completes the proof.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Sep 2 at 4:09









        Shalop

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