Probability that a von Mises - Fisher vector has a larger angle than a uniform distributed vector












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My calculus is a bit rusty and I need to calculate the following.
I have two independent random vectors $X,Y$.



$X$ is a unit vector, von Mises-Fisher distributed with direction $e_1$ on the $n-1$ dimensional sphere in $mathbb{R}^n$, i.e., $f(x ;mu,kappa) = Cexp(kappa cdot mu^tx)$ with $mu=(1,0,...,0)$ ,$kappa geq0$ and $C$ is a constant dependent on $kappa,n$.



$Y$ is a unit vector, uniformly distributed on the $n-1$ dimensional sphere in $mathbb{R}^n$.



I would like to calculate the probability that the angle $X$ creates with $e_1$ is greater than the angle $Y$ creates with $e_1$ as a function of $kappa$. For example, if $kappa = 0$ then this probability is $frac12$.



How do I approach this?










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    0












    $begingroup$


    My calculus is a bit rusty and I need to calculate the following.
    I have two independent random vectors $X,Y$.



    $X$ is a unit vector, von Mises-Fisher distributed with direction $e_1$ on the $n-1$ dimensional sphere in $mathbb{R}^n$, i.e., $f(x ;mu,kappa) = Cexp(kappa cdot mu^tx)$ with $mu=(1,0,...,0)$ ,$kappa geq0$ and $C$ is a constant dependent on $kappa,n$.



    $Y$ is a unit vector, uniformly distributed on the $n-1$ dimensional sphere in $mathbb{R}^n$.



    I would like to calculate the probability that the angle $X$ creates with $e_1$ is greater than the angle $Y$ creates with $e_1$ as a function of $kappa$. For example, if $kappa = 0$ then this probability is $frac12$.



    How do I approach this?










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      My calculus is a bit rusty and I need to calculate the following.
      I have two independent random vectors $X,Y$.



      $X$ is a unit vector, von Mises-Fisher distributed with direction $e_1$ on the $n-1$ dimensional sphere in $mathbb{R}^n$, i.e., $f(x ;mu,kappa) = Cexp(kappa cdot mu^tx)$ with $mu=(1,0,...,0)$ ,$kappa geq0$ and $C$ is a constant dependent on $kappa,n$.



      $Y$ is a unit vector, uniformly distributed on the $n-1$ dimensional sphere in $mathbb{R}^n$.



      I would like to calculate the probability that the angle $X$ creates with $e_1$ is greater than the angle $Y$ creates with $e_1$ as a function of $kappa$. For example, if $kappa = 0$ then this probability is $frac12$.



      How do I approach this?










      share|cite|improve this question











      $endgroup$




      My calculus is a bit rusty and I need to calculate the following.
      I have two independent random vectors $X,Y$.



      $X$ is a unit vector, von Mises-Fisher distributed with direction $e_1$ on the $n-1$ dimensional sphere in $mathbb{R}^n$, i.e., $f(x ;mu,kappa) = Cexp(kappa cdot mu^tx)$ with $mu=(1,0,...,0)$ ,$kappa geq0$ and $C$ is a constant dependent on $kappa,n$.



      $Y$ is a unit vector, uniformly distributed on the $n-1$ dimensional sphere in $mathbb{R}^n$.



      I would like to calculate the probability that the angle $X$ creates with $e_1$ is greater than the angle $Y$ creates with $e_1$ as a function of $kappa$. For example, if $kappa = 0$ then this probability is $frac12$.



      How do I approach this?







      calculus multivariable-calculus probability-distributions






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 12 at 14:34







      catch22

















      asked Jan 12 at 13:30









      catch22catch22

      1,3361122




      1,3361122






















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