A nice power sum inequality












2












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Hello I have this theorem to propose :




Let $a_i$ be $n$ real positive numbers such that $sum_{i=1}^{n}a_i=n$ and $a_{n+1}=a_1$ then we have :
$$sum_{i=1}^{n}a_i^{a_i a_{i+1}+n}geq n$$




For $n=2$ you can apply Jensen's inequality and am-gm for two variables to get :



$$a^{ab+n}+b^{ab+n}geq 2(frac{a+b}{2})^{ab+n}geq 2(frac{a+b}{2})^{(frac{a+b}{2})^2+n}geq 2 $$ with $a+b=2$



So if we make the problem symmetric we get :



$$sum_{i=1}^{n}a_i^{a_i a_{i+1}+n}+sum_{i=1}^{n}a_{i+1}^{a_i a_{i+1}+n}geq 2n$$



But we have $n$ conditions instead of one condition .



So if you have a proof it would be nice .



Thanks in advance .










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$endgroup$

















    2












    $begingroup$


    Hello I have this theorem to propose :




    Let $a_i$ be $n$ real positive numbers such that $sum_{i=1}^{n}a_i=n$ and $a_{n+1}=a_1$ then we have :
    $$sum_{i=1}^{n}a_i^{a_i a_{i+1}+n}geq n$$




    For $n=2$ you can apply Jensen's inequality and am-gm for two variables to get :



    $$a^{ab+n}+b^{ab+n}geq 2(frac{a+b}{2})^{ab+n}geq 2(frac{a+b}{2})^{(frac{a+b}{2})^2+n}geq 2 $$ with $a+b=2$



    So if we make the problem symmetric we get :



    $$sum_{i=1}^{n}a_i^{a_i a_{i+1}+n}+sum_{i=1}^{n}a_{i+1}^{a_i a_{i+1}+n}geq 2n$$



    But we have $n$ conditions instead of one condition .



    So if you have a proof it would be nice .



    Thanks in advance .










    share|cite|improve this question









    $endgroup$















      2












      2








      2


      2



      $begingroup$


      Hello I have this theorem to propose :




      Let $a_i$ be $n$ real positive numbers such that $sum_{i=1}^{n}a_i=n$ and $a_{n+1}=a_1$ then we have :
      $$sum_{i=1}^{n}a_i^{a_i a_{i+1}+n}geq n$$




      For $n=2$ you can apply Jensen's inequality and am-gm for two variables to get :



      $$a^{ab+n}+b^{ab+n}geq 2(frac{a+b}{2})^{ab+n}geq 2(frac{a+b}{2})^{(frac{a+b}{2})^2+n}geq 2 $$ with $a+b=2$



      So if we make the problem symmetric we get :



      $$sum_{i=1}^{n}a_i^{a_i a_{i+1}+n}+sum_{i=1}^{n}a_{i+1}^{a_i a_{i+1}+n}geq 2n$$



      But we have $n$ conditions instead of one condition .



      So if you have a proof it would be nice .



      Thanks in advance .










      share|cite|improve this question









      $endgroup$




      Hello I have this theorem to propose :




      Let $a_i$ be $n$ real positive numbers such that $sum_{i=1}^{n}a_i=n$ and $a_{n+1}=a_1$ then we have :
      $$sum_{i=1}^{n}a_i^{a_i a_{i+1}+n}geq n$$




      For $n=2$ you can apply Jensen's inequality and am-gm for two variables to get :



      $$a^{ab+n}+b^{ab+n}geq 2(frac{a+b}{2})^{ab+n}geq 2(frac{a+b}{2})^{(frac{a+b}{2})^2+n}geq 2 $$ with $a+b=2$



      So if we make the problem symmetric we get :



      $$sum_{i=1}^{n}a_i^{a_i a_{i+1}+n}+sum_{i=1}^{n}a_{i+1}^{a_i a_{i+1}+n}geq 2n$$



      But we have $n$ conditions instead of one condition .



      So if you have a proof it would be nice .



      Thanks in advance .







      real-analysis inequality






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      asked Jan 18 at 13:13









      FatsWallersFatsWallers

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