Dual spaces of uniformly convex Banach spaces












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I am interested in the dual spaces of uniformly convex Banach spaces. Given a uniformly convex Banach space $X$, can anything be said about uniform convexity of its dual space $X^*$? Or given a uniformly convex dual space $X^*$, can anything be said about the uniform convexity of $X$?



I would like links to any papers discussing these points, or any counterexamples. Thank you.










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    $begingroup$


    I am interested in the dual spaces of uniformly convex Banach spaces. Given a uniformly convex Banach space $X$, can anything be said about uniform convexity of its dual space $X^*$? Or given a uniformly convex dual space $X^*$, can anything be said about the uniform convexity of $X$?



    I would like links to any papers discussing these points, or any counterexamples. Thank you.










    share|cite|improve this question









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      2








      2





      $begingroup$


      I am interested in the dual spaces of uniformly convex Banach spaces. Given a uniformly convex Banach space $X$, can anything be said about uniform convexity of its dual space $X^*$? Or given a uniformly convex dual space $X^*$, can anything be said about the uniform convexity of $X$?



      I would like links to any papers discussing these points, or any counterexamples. Thank you.










      share|cite|improve this question









      $endgroup$




      I am interested in the dual spaces of uniformly convex Banach spaces. Given a uniformly convex Banach space $X$, can anything be said about uniform convexity of its dual space $X^*$? Or given a uniformly convex dual space $X^*$, can anything be said about the uniform convexity of $X$?



      I would like links to any papers discussing these points, or any counterexamples. Thank you.







      functional-analysis reference-request banach-spaces






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      asked Dec 16 '18 at 12:54









      talfredtalfred

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          $begingroup$

          A Banach space is uniformly convex if and only if its dual is uniformly smooth. Also, since any uniformly convex Banach space is reflexive, this goes both ways, and any uniformly smooth Banach space is also reflexive. This can all be found on the Wikipedia articles for these properties, and they contain references at the bottom.



          EDIT: Because uniformly convex and uniformly smooth are independent, we can find Banach spaces that are uniformly convex but which have a dual space that is not, and vise versa. Same for uniformly smooth.



          Example: The norm $|cdot|_1+|cdot|_2$ is uniformly convex, but not uniformly smooth if $dim Xgeq2$. Hence its dual is uniformly smooth, but not uniformly convex.






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            $begingroup$
            "Because uniformly convex and uniformly smooth are mutually exclusive..." What about Hilbert Spaces?
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:09










          • $begingroup$
            Mutually exclusive means any combination of the two can appear. Hilbert spaces are just an example where both properties are held. The norm $|cdot|_p$ for $pin{1,infty}$ is neither, and I already gave examples where either one is held, while the other is not.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:10






          • 1




            $begingroup$
            I think you mean "independent" in that case. Mutually exclusive means that both cannot simultaneously occur.
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:12








          • 2




            $begingroup$
            Can't argue with that. I edited the post.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:13











          Your Answer





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          $begingroup$

          A Banach space is uniformly convex if and only if its dual is uniformly smooth. Also, since any uniformly convex Banach space is reflexive, this goes both ways, and any uniformly smooth Banach space is also reflexive. This can all be found on the Wikipedia articles for these properties, and they contain references at the bottom.



          EDIT: Because uniformly convex and uniformly smooth are independent, we can find Banach spaces that are uniformly convex but which have a dual space that is not, and vise versa. Same for uniformly smooth.



          Example: The norm $|cdot|_1+|cdot|_2$ is uniformly convex, but not uniformly smooth if $dim Xgeq2$. Hence its dual is uniformly smooth, but not uniformly convex.






          share|cite|improve this answer











          $endgroup$









          • 1




            $begingroup$
            "Because uniformly convex and uniformly smooth are mutually exclusive..." What about Hilbert Spaces?
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:09










          • $begingroup$
            Mutually exclusive means any combination of the two can appear. Hilbert spaces are just an example where both properties are held. The norm $|cdot|_p$ for $pin{1,infty}$ is neither, and I already gave examples where either one is held, while the other is not.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:10






          • 1




            $begingroup$
            I think you mean "independent" in that case. Mutually exclusive means that both cannot simultaneously occur.
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:12








          • 2




            $begingroup$
            Can't argue with that. I edited the post.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:13
















          3












          $begingroup$

          A Banach space is uniformly convex if and only if its dual is uniformly smooth. Also, since any uniformly convex Banach space is reflexive, this goes both ways, and any uniformly smooth Banach space is also reflexive. This can all be found on the Wikipedia articles for these properties, and they contain references at the bottom.



          EDIT: Because uniformly convex and uniformly smooth are independent, we can find Banach spaces that are uniformly convex but which have a dual space that is not, and vise versa. Same for uniformly smooth.



          Example: The norm $|cdot|_1+|cdot|_2$ is uniformly convex, but not uniformly smooth if $dim Xgeq2$. Hence its dual is uniformly smooth, but not uniformly convex.






          share|cite|improve this answer











          $endgroup$









          • 1




            $begingroup$
            "Because uniformly convex and uniformly smooth are mutually exclusive..." What about Hilbert Spaces?
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:09










          • $begingroup$
            Mutually exclusive means any combination of the two can appear. Hilbert spaces are just an example where both properties are held. The norm $|cdot|_p$ for $pin{1,infty}$ is neither, and I already gave examples where either one is held, while the other is not.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:10






          • 1




            $begingroup$
            I think you mean "independent" in that case. Mutually exclusive means that both cannot simultaneously occur.
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:12








          • 2




            $begingroup$
            Can't argue with that. I edited the post.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:13














          3












          3








          3





          $begingroup$

          A Banach space is uniformly convex if and only if its dual is uniformly smooth. Also, since any uniformly convex Banach space is reflexive, this goes both ways, and any uniformly smooth Banach space is also reflexive. This can all be found on the Wikipedia articles for these properties, and they contain references at the bottom.



          EDIT: Because uniformly convex and uniformly smooth are independent, we can find Banach spaces that are uniformly convex but which have a dual space that is not, and vise versa. Same for uniformly smooth.



          Example: The norm $|cdot|_1+|cdot|_2$ is uniformly convex, but not uniformly smooth if $dim Xgeq2$. Hence its dual is uniformly smooth, but not uniformly convex.






          share|cite|improve this answer











          $endgroup$



          A Banach space is uniformly convex if and only if its dual is uniformly smooth. Also, since any uniformly convex Banach space is reflexive, this goes both ways, and any uniformly smooth Banach space is also reflexive. This can all be found on the Wikipedia articles for these properties, and they contain references at the bottom.



          EDIT: Because uniformly convex and uniformly smooth are independent, we can find Banach spaces that are uniformly convex but which have a dual space that is not, and vise versa. Same for uniformly smooth.



          Example: The norm $|cdot|_1+|cdot|_2$ is uniformly convex, but not uniformly smooth if $dim Xgeq2$. Hence its dual is uniformly smooth, but not uniformly convex.







          share|cite|improve this answer














          share|cite|improve this answer



          share|cite|improve this answer








          edited Dec 16 '18 at 13:12

























          answered Dec 16 '18 at 13:02









          SmileyCraftSmileyCraft

          3,401516




          3,401516








          • 1




            $begingroup$
            "Because uniformly convex and uniformly smooth are mutually exclusive..." What about Hilbert Spaces?
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:09










          • $begingroup$
            Mutually exclusive means any combination of the two can appear. Hilbert spaces are just an example where both properties are held. The norm $|cdot|_p$ for $pin{1,infty}$ is neither, and I already gave examples where either one is held, while the other is not.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:10






          • 1




            $begingroup$
            I think you mean "independent" in that case. Mutually exclusive means that both cannot simultaneously occur.
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:12








          • 2




            $begingroup$
            Can't argue with that. I edited the post.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:13














          • 1




            $begingroup$
            "Because uniformly convex and uniformly smooth are mutually exclusive..." What about Hilbert Spaces?
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:09










          • $begingroup$
            Mutually exclusive means any combination of the two can appear. Hilbert spaces are just an example where both properties are held. The norm $|cdot|_p$ for $pin{1,infty}$ is neither, and I already gave examples where either one is held, while the other is not.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:10






          • 1




            $begingroup$
            I think you mean "independent" in that case. Mutually exclusive means that both cannot simultaneously occur.
            $endgroup$
            – Theo Bendit
            Dec 16 '18 at 13:12








          • 2




            $begingroup$
            Can't argue with that. I edited the post.
            $endgroup$
            – SmileyCraft
            Dec 16 '18 at 13:13








          1




          1




          $begingroup$
          "Because uniformly convex and uniformly smooth are mutually exclusive..." What about Hilbert Spaces?
          $endgroup$
          – Theo Bendit
          Dec 16 '18 at 13:09




          $begingroup$
          "Because uniformly convex and uniformly smooth are mutually exclusive..." What about Hilbert Spaces?
          $endgroup$
          – Theo Bendit
          Dec 16 '18 at 13:09












          $begingroup$
          Mutually exclusive means any combination of the two can appear. Hilbert spaces are just an example where both properties are held. The norm $|cdot|_p$ for $pin{1,infty}$ is neither, and I already gave examples where either one is held, while the other is not.
          $endgroup$
          – SmileyCraft
          Dec 16 '18 at 13:10




          $begingroup$
          Mutually exclusive means any combination of the two can appear. Hilbert spaces are just an example where both properties are held. The norm $|cdot|_p$ for $pin{1,infty}$ is neither, and I already gave examples where either one is held, while the other is not.
          $endgroup$
          – SmileyCraft
          Dec 16 '18 at 13:10




          1




          1




          $begingroup$
          I think you mean "independent" in that case. Mutually exclusive means that both cannot simultaneously occur.
          $endgroup$
          – Theo Bendit
          Dec 16 '18 at 13:12






          $begingroup$
          I think you mean "independent" in that case. Mutually exclusive means that both cannot simultaneously occur.
          $endgroup$
          – Theo Bendit
          Dec 16 '18 at 13:12






          2




          2




          $begingroup$
          Can't argue with that. I edited the post.
          $endgroup$
          – SmileyCraft
          Dec 16 '18 at 13:13




          $begingroup$
          Can't argue with that. I edited the post.
          $endgroup$
          – SmileyCraft
          Dec 16 '18 at 13:13


















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