Simple Consequences of Goldstine's Theorem The 2019 Stack Overflow Developer Survey Results...

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Simple Consequences of Goldstine's Theorem



The 2019 Stack Overflow Developer Survey Results Are InConsequence of metrizability proof - disregard, the question is an errorTurning an isometric embedding into a homeomorphismThe the image of the unit ball in X is weak-* dense in the unit ball of X**Unit ball separable $Longrightarrow$ Space separableIf $T:X rightarrow Y$ is a linear operator and $r>0$ such that $r cdot B_Y subseteq T(B_X)$, show $y ||x|| leq M ||y||$.Compactness of the closed unit ball in the weak* topology: the Banach–Alaoglu theoremCan I restrict the condition on the Goldstine's theorem?Metamathematics of the Banach space consequences of the Baire category theoremUsing the Banach-Alaoglu Theorem to show that if $X$ is reflexive then $B_X$ is weakly compact.If a normed space $X$ is reflexive, then $Q(B_X)=B_{X^{**}}$.












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$begingroup$


For a normed space $ X $, let $ J : X to X^{**} $ be the natural embedding of $ X $ into $ X^{**} $, and let $ B_X $ and $ B_{X^{**}} $ denote the closed unit balls of $ X $ and $ X^{**} $ respectively.



Goldstine's Theorem: If $ X $ is a normed space then $ J(B_X) $ is weak* dense in $ B_{X^{**}} $.



I want to see the significance of this theorem but I can't find many consequences to this result. Does anyone know of any relatively simple/nice/easy-to-understand consequences of Goldstine's theorem that a beginner in learning functional analysis might be able to understand?



Thanks!










share|cite|improve this question









$endgroup$

















    0












    $begingroup$


    For a normed space $ X $, let $ J : X to X^{**} $ be the natural embedding of $ X $ into $ X^{**} $, and let $ B_X $ and $ B_{X^{**}} $ denote the closed unit balls of $ X $ and $ X^{**} $ respectively.



    Goldstine's Theorem: If $ X $ is a normed space then $ J(B_X) $ is weak* dense in $ B_{X^{**}} $.



    I want to see the significance of this theorem but I can't find many consequences to this result. Does anyone know of any relatively simple/nice/easy-to-understand consequences of Goldstine's theorem that a beginner in learning functional analysis might be able to understand?



    Thanks!










    share|cite|improve this question









    $endgroup$















      0












      0








      0





      $begingroup$


      For a normed space $ X $, let $ J : X to X^{**} $ be the natural embedding of $ X $ into $ X^{**} $, and let $ B_X $ and $ B_{X^{**}} $ denote the closed unit balls of $ X $ and $ X^{**} $ respectively.



      Goldstine's Theorem: If $ X $ is a normed space then $ J(B_X) $ is weak* dense in $ B_{X^{**}} $.



      I want to see the significance of this theorem but I can't find many consequences to this result. Does anyone know of any relatively simple/nice/easy-to-understand consequences of Goldstine's theorem that a beginner in learning functional analysis might be able to understand?



      Thanks!










      share|cite|improve this question









      $endgroup$




      For a normed space $ X $, let $ J : X to X^{**} $ be the natural embedding of $ X $ into $ X^{**} $, and let $ B_X $ and $ B_{X^{**}} $ denote the closed unit balls of $ X $ and $ X^{**} $ respectively.



      Goldstine's Theorem: If $ X $ is a normed space then $ J(B_X) $ is weak* dense in $ B_{X^{**}} $.



      I want to see the significance of this theorem but I can't find many consequences to this result. Does anyone know of any relatively simple/nice/easy-to-understand consequences of Goldstine's theorem that a beginner in learning functional analysis might be able to understand?



      Thanks!







      functional-analysis






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked Mar 21 at 4:09









      LMWLMW

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