Fubini Thm to prove $int _{[0,infty)^n setminus [0,1]^n} frac{1}{sum_1^n x_i^{a_i}} dlambda <infty...












2












$begingroup$


This question have an answer which doesn't use Fibini-Tonelli here:



A problem in n-dimesnsional Lebesgue measure



The proposition states that $a_1,a_2,...,a_n >0$:
$int _{[0,infty)^n setminus [0,1]^n} frac{1}{sum_1^n x_i^{a_i}} dlambda <infty Leftrightarrow sum_1^nfrac{1}{a_i} <1$



I tried to work it out using Fubini Tonelli theorem, and by induction, by splitting the integral to 2 integral of $l,m$ dimensions such that $l+m=n$. I tried to work out how to split that $sum_1 ^{n} frac{1}{a_i}$ in order to apply the induction assumption. But I didn't succeed to find a way to do so.



I wish for a solution using Fubini theorem, I also hope it is not considered a duplicate, please let me know if so.










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$endgroup$

















    2












    $begingroup$


    This question have an answer which doesn't use Fibini-Tonelli here:



    A problem in n-dimesnsional Lebesgue measure



    The proposition states that $a_1,a_2,...,a_n >0$:
    $int _{[0,infty)^n setminus [0,1]^n} frac{1}{sum_1^n x_i^{a_i}} dlambda <infty Leftrightarrow sum_1^nfrac{1}{a_i} <1$



    I tried to work it out using Fubini Tonelli theorem, and by induction, by splitting the integral to 2 integral of $l,m$ dimensions such that $l+m=n$. I tried to work out how to split that $sum_1 ^{n} frac{1}{a_i}$ in order to apply the induction assumption. But I didn't succeed to find a way to do so.



    I wish for a solution using Fubini theorem, I also hope it is not considered a duplicate, please let me know if so.










    share|cite|improve this question











    $endgroup$















      2












      2








      2





      $begingroup$


      This question have an answer which doesn't use Fibini-Tonelli here:



      A problem in n-dimesnsional Lebesgue measure



      The proposition states that $a_1,a_2,...,a_n >0$:
      $int _{[0,infty)^n setminus [0,1]^n} frac{1}{sum_1^n x_i^{a_i}} dlambda <infty Leftrightarrow sum_1^nfrac{1}{a_i} <1$



      I tried to work it out using Fubini Tonelli theorem, and by induction, by splitting the integral to 2 integral of $l,m$ dimensions such that $l+m=n$. I tried to work out how to split that $sum_1 ^{n} frac{1}{a_i}$ in order to apply the induction assumption. But I didn't succeed to find a way to do so.



      I wish for a solution using Fubini theorem, I also hope it is not considered a duplicate, please let me know if so.










      share|cite|improve this question











      $endgroup$




      This question have an answer which doesn't use Fibini-Tonelli here:



      A problem in n-dimesnsional Lebesgue measure



      The proposition states that $a_1,a_2,...,a_n >0$:
      $int _{[0,infty)^n setminus [0,1]^n} frac{1}{sum_1^n x_i^{a_i}} dlambda <infty Leftrightarrow sum_1^nfrac{1}{a_i} <1$



      I tried to work it out using Fubini Tonelli theorem, and by induction, by splitting the integral to 2 integral of $l,m$ dimensions such that $l+m=n$. I tried to work out how to split that $sum_1 ^{n} frac{1}{a_i}$ in order to apply the induction assumption. But I didn't succeed to find a way to do so.



      I wish for a solution using Fubini theorem, I also hope it is not considered a duplicate, please let me know if so.







      real-analysis lebesgue-integral






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      share|cite|improve this question













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      share|cite|improve this question








      edited Jan 20 at 16:37







      dan

















      asked Jan 20 at 9:06









      dandan

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      571613






















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