Connection between $operatorname{Var}(M^n v)$ and largest eigenvalue of $M$












1












$begingroup$


In a proof I am trying to understand, the following is stated:



$ M$ is a non-random matrix with eigenvalues $lambda_i$, $v$ is a random vector, $n$ is a scalar,



$operatorname{Var}(M^n v) ge max(|lambda_i|)^n
$



As I copied this from the blackboard, I might have made a mistake. Our script says



$ lim_{ntoinfty}operatorname{Var}(M^n v) = infty mbox{ if } max(|lambda_i|) > 1
$



(which would be implied by the first inequality).



If anyone could explain why this holds, or point me to a paper/book where this is explained I would very much appreciate it.










share|cite|improve this question











$endgroup$

















    1












    $begingroup$


    In a proof I am trying to understand, the following is stated:



    $ M$ is a non-random matrix with eigenvalues $lambda_i$, $v$ is a random vector, $n$ is a scalar,



    $operatorname{Var}(M^n v) ge max(|lambda_i|)^n
    $



    As I copied this from the blackboard, I might have made a mistake. Our script says



    $ lim_{ntoinfty}operatorname{Var}(M^n v) = infty mbox{ if } max(|lambda_i|) > 1
    $



    (which would be implied by the first inequality).



    If anyone could explain why this holds, or point me to a paper/book where this is explained I would very much appreciate it.










    share|cite|improve this question











    $endgroup$















      1












      1








      1





      $begingroup$


      In a proof I am trying to understand, the following is stated:



      $ M$ is a non-random matrix with eigenvalues $lambda_i$, $v$ is a random vector, $n$ is a scalar,



      $operatorname{Var}(M^n v) ge max(|lambda_i|)^n
      $



      As I copied this from the blackboard, I might have made a mistake. Our script says



      $ lim_{ntoinfty}operatorname{Var}(M^n v) = infty mbox{ if } max(|lambda_i|) > 1
      $



      (which would be implied by the first inequality).



      If anyone could explain why this holds, or point me to a paper/book where this is explained I would very much appreciate it.










      share|cite|improve this question











      $endgroup$




      In a proof I am trying to understand, the following is stated:



      $ M$ is a non-random matrix with eigenvalues $lambda_i$, $v$ is a random vector, $n$ is a scalar,



      $operatorname{Var}(M^n v) ge max(|lambda_i|)^n
      $



      As I copied this from the blackboard, I might have made a mistake. Our script says



      $ lim_{ntoinfty}operatorname{Var}(M^n v) = infty mbox{ if } max(|lambda_i|) > 1
      $



      (which would be implied by the first inequality).



      If anyone could explain why this holds, or point me to a paper/book where this is explained I would very much appreciate it.







      statistics eigenvalues-eigenvectors random-variables covariance variance






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      edited Dec 31 '18 at 21:12









      Davide Giraudo

      128k17154268




      128k17154268










      asked Dec 27 '18 at 12:10









      CariieCariie

      133




      133






















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