Prove $int_Rfg,dmleq|f|_p^{1-p/r}|g|_p^{1-q/r}(int_Rf^pg^q,dm)^{1/r}$, where $1leq pleqinfty$ and...












-2












$begingroup$


Let $f$, $g$ be positive real functions. And $f in L^p(R)$, $g in L^q(R)$, and $1 leqslant p,q <infty$. Then $fg in L^1(R)$ and
$$ int_R fg ,dm;leqslant; |f|_p^{1-p/r}|g|_p^{1-q/r}left(int_R f^pg^q ,dmright)^{1/r}$$
Where
$$1leqslant p leqslant +infty quadtext{and}quadfrac{1}{r}=frac{1}{p}+frac{1}{q}-1$$










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  • $begingroup$
    Please give more context. Providing context not only assures that this is not simply copied from a homework assignment, but also allows answers to be better directed at where the problem lies and to be within the proper scope. Please avoid "I have no clue" questions. Defining keywords and trying a simpler, similar problem often helps.
    $endgroup$
    – robjohn
    Dec 27 '18 at 11:03










  • $begingroup$
    Shouldn't the norm for $g$ be $q$? While you're correcting that, why not add some context? I have an answer, but unless there is more context, it would not be right to post it.
    $endgroup$
    – robjohn
    Dec 28 '18 at 8:11


















-2












$begingroup$


Let $f$, $g$ be positive real functions. And $f in L^p(R)$, $g in L^q(R)$, and $1 leqslant p,q <infty$. Then $fg in L^1(R)$ and
$$ int_R fg ,dm;leqslant; |f|_p^{1-p/r}|g|_p^{1-q/r}left(int_R f^pg^q ,dmright)^{1/r}$$
Where
$$1leqslant p leqslant +infty quadtext{and}quadfrac{1}{r}=frac{1}{p}+frac{1}{q}-1$$










share|cite|improve this question











$endgroup$












  • $begingroup$
    Please give more context. Providing context not only assures that this is not simply copied from a homework assignment, but also allows answers to be better directed at where the problem lies and to be within the proper scope. Please avoid "I have no clue" questions. Defining keywords and trying a simpler, similar problem often helps.
    $endgroup$
    – robjohn
    Dec 27 '18 at 11:03










  • $begingroup$
    Shouldn't the norm for $g$ be $q$? While you're correcting that, why not add some context? I have an answer, but unless there is more context, it would not be right to post it.
    $endgroup$
    – robjohn
    Dec 28 '18 at 8:11
















-2












-2








-2





$begingroup$


Let $f$, $g$ be positive real functions. And $f in L^p(R)$, $g in L^q(R)$, and $1 leqslant p,q <infty$. Then $fg in L^1(R)$ and
$$ int_R fg ,dm;leqslant; |f|_p^{1-p/r}|g|_p^{1-q/r}left(int_R f^pg^q ,dmright)^{1/r}$$
Where
$$1leqslant p leqslant +infty quadtext{and}quadfrac{1}{r}=frac{1}{p}+frac{1}{q}-1$$










share|cite|improve this question











$endgroup$




Let $f$, $g$ be positive real functions. And $f in L^p(R)$, $g in L^q(R)$, and $1 leqslant p,q <infty$. Then $fg in L^1(R)$ and
$$ int_R fg ,dm;leqslant; |f|_p^{1-p/r}|g|_p^{1-q/r}left(int_R f^pg^q ,dmright)^{1/r}$$
Where
$$1leqslant p leqslant +infty quadtext{and}quadfrac{1}{r}=frac{1}{p}+frac{1}{q}-1$$







integration measure-theory lebesgue-integral holder-inequality






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edited Dec 27 '18 at 10:56









Blue

48.6k870154




48.6k870154










asked Dec 27 '18 at 10:24









nnMannnMan

464




464












  • $begingroup$
    Please give more context. Providing context not only assures that this is not simply copied from a homework assignment, but also allows answers to be better directed at where the problem lies and to be within the proper scope. Please avoid "I have no clue" questions. Defining keywords and trying a simpler, similar problem often helps.
    $endgroup$
    – robjohn
    Dec 27 '18 at 11:03










  • $begingroup$
    Shouldn't the norm for $g$ be $q$? While you're correcting that, why not add some context? I have an answer, but unless there is more context, it would not be right to post it.
    $endgroup$
    – robjohn
    Dec 28 '18 at 8:11




















  • $begingroup$
    Please give more context. Providing context not only assures that this is not simply copied from a homework assignment, but also allows answers to be better directed at where the problem lies and to be within the proper scope. Please avoid "I have no clue" questions. Defining keywords and trying a simpler, similar problem often helps.
    $endgroup$
    – robjohn
    Dec 27 '18 at 11:03










  • $begingroup$
    Shouldn't the norm for $g$ be $q$? While you're correcting that, why not add some context? I have an answer, but unless there is more context, it would not be right to post it.
    $endgroup$
    – robjohn
    Dec 28 '18 at 8:11


















$begingroup$
Please give more context. Providing context not only assures that this is not simply copied from a homework assignment, but also allows answers to be better directed at where the problem lies and to be within the proper scope. Please avoid "I have no clue" questions. Defining keywords and trying a simpler, similar problem often helps.
$endgroup$
– robjohn
Dec 27 '18 at 11:03




$begingroup$
Please give more context. Providing context not only assures that this is not simply copied from a homework assignment, but also allows answers to be better directed at where the problem lies and to be within the proper scope. Please avoid "I have no clue" questions. Defining keywords and trying a simpler, similar problem often helps.
$endgroup$
– robjohn
Dec 27 '18 at 11:03












$begingroup$
Shouldn't the norm for $g$ be $q$? While you're correcting that, why not add some context? I have an answer, but unless there is more context, it would not be right to post it.
$endgroup$
– robjohn
Dec 28 '18 at 8:11






$begingroup$
Shouldn't the norm for $g$ be $q$? While you're correcting that, why not add some context? I have an answer, but unless there is more context, it would not be right to post it.
$endgroup$
– robjohn
Dec 28 '18 at 8:11












1 Answer
1






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$begingroup$

Hints: I suppose $1+frac 1 r =frac 1 p +frac 1 q$. Write $fg$ as $f^{p/r}g^{q/r} f^{1-p/r}g^{1-q/r}$ and apply Holder with conjugate indices $r$ and $frac r {r-1}$. You will get $(int f^{p}g^{q})^{1/r}$ as one of the factors. Now applying another Holder to complete the proof is fairly straightfoward.






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  • $begingroup$
    Actually, the condition is $frac1r=frac1p+frac1q-1$.
    $endgroup$
    – robjohn
    Dec 28 '18 at 8:09











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1 Answer
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active

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1 Answer
1






active

oldest

votes









active

oldest

votes






active

oldest

votes









0












$begingroup$

Hints: I suppose $1+frac 1 r =frac 1 p +frac 1 q$. Write $fg$ as $f^{p/r}g^{q/r} f^{1-p/r}g^{1-q/r}$ and apply Holder with conjugate indices $r$ and $frac r {r-1}$. You will get $(int f^{p}g^{q})^{1/r}$ as one of the factors. Now applying another Holder to complete the proof is fairly straightfoward.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    Actually, the condition is $frac1r=frac1p+frac1q-1$.
    $endgroup$
    – robjohn
    Dec 28 '18 at 8:09
















0












$begingroup$

Hints: I suppose $1+frac 1 r =frac 1 p +frac 1 q$. Write $fg$ as $f^{p/r}g^{q/r} f^{1-p/r}g^{1-q/r}$ and apply Holder with conjugate indices $r$ and $frac r {r-1}$. You will get $(int f^{p}g^{q})^{1/r}$ as one of the factors. Now applying another Holder to complete the proof is fairly straightfoward.






share|cite|improve this answer











$endgroup$













  • $begingroup$
    Actually, the condition is $frac1r=frac1p+frac1q-1$.
    $endgroup$
    – robjohn
    Dec 28 '18 at 8:09














0












0








0





$begingroup$

Hints: I suppose $1+frac 1 r =frac 1 p +frac 1 q$. Write $fg$ as $f^{p/r}g^{q/r} f^{1-p/r}g^{1-q/r}$ and apply Holder with conjugate indices $r$ and $frac r {r-1}$. You will get $(int f^{p}g^{q})^{1/r}$ as one of the factors. Now applying another Holder to complete the proof is fairly straightfoward.






share|cite|improve this answer











$endgroup$



Hints: I suppose $1+frac 1 r =frac 1 p +frac 1 q$. Write $fg$ as $f^{p/r}g^{q/r} f^{1-p/r}g^{1-q/r}$ and apply Holder with conjugate indices $r$ and $frac r {r-1}$. You will get $(int f^{p}g^{q})^{1/r}$ as one of the factors. Now applying another Holder to complete the proof is fairly straightfoward.







share|cite|improve this answer














share|cite|improve this answer



share|cite|improve this answer








edited Dec 28 '18 at 8:20

























answered Dec 27 '18 at 10:34









Kavi Rama MurthyKavi Rama Murthy

62.6k42262




62.6k42262












  • $begingroup$
    Actually, the condition is $frac1r=frac1p+frac1q-1$.
    $endgroup$
    – robjohn
    Dec 28 '18 at 8:09


















  • $begingroup$
    Actually, the condition is $frac1r=frac1p+frac1q-1$.
    $endgroup$
    – robjohn
    Dec 28 '18 at 8:09
















$begingroup$
Actually, the condition is $frac1r=frac1p+frac1q-1$.
$endgroup$
– robjohn
Dec 28 '18 at 8:09




$begingroup$
Actually, the condition is $frac1r=frac1p+frac1q-1$.
$endgroup$
– robjohn
Dec 28 '18 at 8:09


















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