Covering Number of $C^mleft[ 0, 1 right]$ in $L^2 left[ 0, 1 right]$












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$begingroup$


Let $m$ be a positive integer, for any $epsilon gt 0$, denote $N(epsilon)$ the covering number of $C^mleft[ 0, 1 right]$ in $L^2 left[ 0, 1 right]$, i.e., the smallest positive integer $N$ such that there exists $N$ functions $f_1, cdots, f_N$ in $C^mleft[ 0, 1 right]$, whose $m$-th derivatives are uniformly bounded by $M$, s.t. for any $f in C^mleft[ 0, 1 right], lVert f^{(m)} rVert leq M$,
begin{equation}
exists 1 leq i leq N, lVert f-f_i rVert_{L^2} lt epsilon.
end{equation}

I conjecture that $log N(epsilon)$ is approximately $C_0 epsilon^{-frac{2}{2m-1}}$ and I believe that there must be some previous results on it, but I didn't find any.










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$endgroup$

















    2












    $begingroup$


    Let $m$ be a positive integer, for any $epsilon gt 0$, denote $N(epsilon)$ the covering number of $C^mleft[ 0, 1 right]$ in $L^2 left[ 0, 1 right]$, i.e., the smallest positive integer $N$ such that there exists $N$ functions $f_1, cdots, f_N$ in $C^mleft[ 0, 1 right]$, whose $m$-th derivatives are uniformly bounded by $M$, s.t. for any $f in C^mleft[ 0, 1 right], lVert f^{(m)} rVert leq M$,
    begin{equation}
    exists 1 leq i leq N, lVert f-f_i rVert_{L^2} lt epsilon.
    end{equation}

    I conjecture that $log N(epsilon)$ is approximately $C_0 epsilon^{-frac{2}{2m-1}}$ and I believe that there must be some previous results on it, but I didn't find any.










    share|cite|improve this question











    $endgroup$















      2












      2








      2


      1



      $begingroup$


      Let $m$ be a positive integer, for any $epsilon gt 0$, denote $N(epsilon)$ the covering number of $C^mleft[ 0, 1 right]$ in $L^2 left[ 0, 1 right]$, i.e., the smallest positive integer $N$ such that there exists $N$ functions $f_1, cdots, f_N$ in $C^mleft[ 0, 1 right]$, whose $m$-th derivatives are uniformly bounded by $M$, s.t. for any $f in C^mleft[ 0, 1 right], lVert f^{(m)} rVert leq M$,
      begin{equation}
      exists 1 leq i leq N, lVert f-f_i rVert_{L^2} lt epsilon.
      end{equation}

      I conjecture that $log N(epsilon)$ is approximately $C_0 epsilon^{-frac{2}{2m-1}}$ and I believe that there must be some previous results on it, but I didn't find any.










      share|cite|improve this question











      $endgroup$




      Let $m$ be a positive integer, for any $epsilon gt 0$, denote $N(epsilon)$ the covering number of $C^mleft[ 0, 1 right]$ in $L^2 left[ 0, 1 right]$, i.e., the smallest positive integer $N$ such that there exists $N$ functions $f_1, cdots, f_N$ in $C^mleft[ 0, 1 right]$, whose $m$-th derivatives are uniformly bounded by $M$, s.t. for any $f in C^mleft[ 0, 1 right], lVert f^{(m)} rVert leq M$,
      begin{equation}
      exists 1 leq i leq N, lVert f-f_i rVert_{L^2} lt epsilon.
      end{equation}

      I conjecture that $log N(epsilon)$ is approximately $C_0 epsilon^{-frac{2}{2m-1}}$ and I believe that there must be some previous results on it, but I didn't find any.







      real-analysis functional-analysis analysis






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      edited Dec 23 '18 at 15:26







      Martin Chow

















      asked Dec 23 '18 at 15:18









      Martin ChowMartin Chow

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