The problem is about the expection of the exitpoint distance for the symmetric random walk.












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$begingroup$


Let $nu(x)$ be a symmetric probability measure with respect to the origin on $xin[-1,1]$ such that $nu({0})neq 1$.



Consider a random walk started at $S_0=0$, denoted $S_n=X_1+cdots+X_n$, where $X_1,X_2, cdots$ are the i.i.d sequences such $X_isim nu(x)$. For some $1leq L<infty$, denote $tau=inf{ngeq0: S_n>L}$.



Let $hbar_{nu,L}=mathbb{E}(S_tau)-L$, in other words, $hbar_{nu,L}$ is the mean value of exitpoint distance from $L$.



$textbf{My question is how to derive the explicit formula for}$ $bf{hbar_{nu,L}}$$textbf{?}$



Mey be one can start by some simple $nu(x)$ and fix $L=1$. Let $mu(x)$ be the probability density function of $nu(x)$, for example,



$textbf{(i)} $ $mu(x)=1/2,~ xin[-1,1];$



$textbf{(ii)} $$mu(x)=frac{2}{pi}sqrt{1-x^2},~ xin[-1,1];$



If possible,could you recommend some relevant papers or books for me? Anyway, any hints or help would be appreciated. Thank you very much.










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$endgroup$

















    1












    $begingroup$


    Let $nu(x)$ be a symmetric probability measure with respect to the origin on $xin[-1,1]$ such that $nu({0})neq 1$.



    Consider a random walk started at $S_0=0$, denoted $S_n=X_1+cdots+X_n$, where $X_1,X_2, cdots$ are the i.i.d sequences such $X_isim nu(x)$. For some $1leq L<infty$, denote $tau=inf{ngeq0: S_n>L}$.



    Let $hbar_{nu,L}=mathbb{E}(S_tau)-L$, in other words, $hbar_{nu,L}$ is the mean value of exitpoint distance from $L$.



    $textbf{My question is how to derive the explicit formula for}$ $bf{hbar_{nu,L}}$$textbf{?}$



    Mey be one can start by some simple $nu(x)$ and fix $L=1$. Let $mu(x)$ be the probability density function of $nu(x)$, for example,



    $textbf{(i)} $ $mu(x)=1/2,~ xin[-1,1];$



    $textbf{(ii)} $$mu(x)=frac{2}{pi}sqrt{1-x^2},~ xin[-1,1];$



    If possible,could you recommend some relevant papers or books for me? Anyway, any hints or help would be appreciated. Thank you very much.










    share|cite|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      Let $nu(x)$ be a symmetric probability measure with respect to the origin on $xin[-1,1]$ such that $nu({0})neq 1$.



      Consider a random walk started at $S_0=0$, denoted $S_n=X_1+cdots+X_n$, where $X_1,X_2, cdots$ are the i.i.d sequences such $X_isim nu(x)$. For some $1leq L<infty$, denote $tau=inf{ngeq0: S_n>L}$.



      Let $hbar_{nu,L}=mathbb{E}(S_tau)-L$, in other words, $hbar_{nu,L}$ is the mean value of exitpoint distance from $L$.



      $textbf{My question is how to derive the explicit formula for}$ $bf{hbar_{nu,L}}$$textbf{?}$



      Mey be one can start by some simple $nu(x)$ and fix $L=1$. Let $mu(x)$ be the probability density function of $nu(x)$, for example,



      $textbf{(i)} $ $mu(x)=1/2,~ xin[-1,1];$



      $textbf{(ii)} $$mu(x)=frac{2}{pi}sqrt{1-x^2},~ xin[-1,1];$



      If possible,could you recommend some relevant papers or books for me? Anyway, any hints or help would be appreciated. Thank you very much.










      share|cite|improve this question









      $endgroup$




      Let $nu(x)$ be a symmetric probability measure with respect to the origin on $xin[-1,1]$ such that $nu({0})neq 1$.



      Consider a random walk started at $S_0=0$, denoted $S_n=X_1+cdots+X_n$, where $X_1,X_2, cdots$ are the i.i.d sequences such $X_isim nu(x)$. For some $1leq L<infty$, denote $tau=inf{ngeq0: S_n>L}$.



      Let $hbar_{nu,L}=mathbb{E}(S_tau)-L$, in other words, $hbar_{nu,L}$ is the mean value of exitpoint distance from $L$.



      $textbf{My question is how to derive the explicit formula for}$ $bf{hbar_{nu,L}}$$textbf{?}$



      Mey be one can start by some simple $nu(x)$ and fix $L=1$. Let $mu(x)$ be the probability density function of $nu(x)$, for example,



      $textbf{(i)} $ $mu(x)=1/2,~ xin[-1,1];$



      $textbf{(ii)} $$mu(x)=frac{2}{pi}sqrt{1-x^2},~ xin[-1,1];$



      If possible,could you recommend some relevant papers or books for me? Anyway, any hints or help would be appreciated. Thank you very much.







      probability probability-theory martingales random-walk stopping-times






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      asked Dec 8 '18 at 5:41









      lang zoulang zou

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