Does convergence in Hilbert-Schmidt norm imply convergence of singular values?












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Let $A$ be a Hilbert-Schmidt operator between two hilbert spaces $H_1$ and $H_2$, with singular value decomposition: $A = sum_n lambda_n u_n otimes v_n$.



Now let $A_i$ be a sequence of operators converging to $A$ in Hilbert-Schmidt norm. Do the singular values of the $A_i$ converge to the singular values of $A$, and if so in what precise sense? What can we say about the singular vectors?



Finally, does this require that $H_1$ and $H_2$ be separable?










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    2












    $begingroup$


    Let $A$ be a Hilbert-Schmidt operator between two hilbert spaces $H_1$ and $H_2$, with singular value decomposition: $A = sum_n lambda_n u_n otimes v_n$.



    Now let $A_i$ be a sequence of operators converging to $A$ in Hilbert-Schmidt norm. Do the singular values of the $A_i$ converge to the singular values of $A$, and if so in what precise sense? What can we say about the singular vectors?



    Finally, does this require that $H_1$ and $H_2$ be separable?










    share|cite|improve this question









    $endgroup$















      2












      2








      2


      1



      $begingroup$


      Let $A$ be a Hilbert-Schmidt operator between two hilbert spaces $H_1$ and $H_2$, with singular value decomposition: $A = sum_n lambda_n u_n otimes v_n$.



      Now let $A_i$ be a sequence of operators converging to $A$ in Hilbert-Schmidt norm. Do the singular values of the $A_i$ converge to the singular values of $A$, and if so in what precise sense? What can we say about the singular vectors?



      Finally, does this require that $H_1$ and $H_2$ be separable?










      share|cite|improve this question









      $endgroup$




      Let $A$ be a Hilbert-Schmidt operator between two hilbert spaces $H_1$ and $H_2$, with singular value decomposition: $A = sum_n lambda_n u_n otimes v_n$.



      Now let $A_i$ be a sequence of operators converging to $A$ in Hilbert-Schmidt norm. Do the singular values of the $A_i$ converge to the singular values of $A$, and if so in what precise sense? What can we say about the singular vectors?



      Finally, does this require that $H_1$ and $H_2$ be separable?







      functional-analysis operator-theory hilbert-spaces spectral-theory singularvalues






      share|cite|improve this question













      share|cite|improve this question











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      share|cite|improve this question










      asked Dec 16 '18 at 9:58









      NeuromathNeuromath

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