Computing $int_0^1 prod_x in mathcalX (p_xy + (1-p_x)) dy$

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How would I compute this integral:
$$int_0^1 prod_x in mathcalX (p_xy + (1-p_x)) dy$$
I have tried using the chain rule and not made any headway on that front. Any advice is welcome.







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  • 2




    Can you agree that $p_x=partial p/partial x$ and explain what $mathcalX$ here is?
    – Fakemistake
    Aug 14 at 11:14










  • @Fakemistake $p_x$ is just a constant. $mathcalX$ is just a set, the cardinality of which governs the degree of the polynomial whose monomials are of the form $(p_xy+(1-p_x))$.
    – Television
    Aug 14 at 11:16







  • 2




    The substitution $u = 1 - y$ simplifies the factors of the integrand to the form $1-p_x u$. The product can then be expanded as a polynomial in $u$, with coefficients expressed as elementary symmetric polynomials of the $p_i$. The integration of the expanded polynomial is straightforward.
    – Blue
    Aug 14 at 11:55














up vote
0
down vote

favorite












How would I compute this integral:
$$int_0^1 prod_x in mathcalX (p_xy + (1-p_x)) dy$$
I have tried using the chain rule and not made any headway on that front. Any advice is welcome.







share|cite|improve this question


















  • 2




    Can you agree that $p_x=partial p/partial x$ and explain what $mathcalX$ here is?
    – Fakemistake
    Aug 14 at 11:14










  • @Fakemistake $p_x$ is just a constant. $mathcalX$ is just a set, the cardinality of which governs the degree of the polynomial whose monomials are of the form $(p_xy+(1-p_x))$.
    – Television
    Aug 14 at 11:16







  • 2




    The substitution $u = 1 - y$ simplifies the factors of the integrand to the form $1-p_x u$. The product can then be expanded as a polynomial in $u$, with coefficients expressed as elementary symmetric polynomials of the $p_i$. The integration of the expanded polynomial is straightforward.
    – Blue
    Aug 14 at 11:55












up vote
0
down vote

favorite









up vote
0
down vote

favorite











How would I compute this integral:
$$int_0^1 prod_x in mathcalX (p_xy + (1-p_x)) dy$$
I have tried using the chain rule and not made any headway on that front. Any advice is welcome.







share|cite|improve this question














How would I compute this integral:
$$int_0^1 prod_x in mathcalX (p_xy + (1-p_x)) dy$$
I have tried using the chain rule and not made any headway on that front. Any advice is welcome.









share|cite|improve this question













share|cite|improve this question




share|cite|improve this question








edited Aug 14 at 11:13









Blue

43.7k868141




43.7k868141










asked Aug 14 at 11:09









Television

13711




13711







  • 2




    Can you agree that $p_x=partial p/partial x$ and explain what $mathcalX$ here is?
    – Fakemistake
    Aug 14 at 11:14










  • @Fakemistake $p_x$ is just a constant. $mathcalX$ is just a set, the cardinality of which governs the degree of the polynomial whose monomials are of the form $(p_xy+(1-p_x))$.
    – Television
    Aug 14 at 11:16







  • 2




    The substitution $u = 1 - y$ simplifies the factors of the integrand to the form $1-p_x u$. The product can then be expanded as a polynomial in $u$, with coefficients expressed as elementary symmetric polynomials of the $p_i$. The integration of the expanded polynomial is straightforward.
    – Blue
    Aug 14 at 11:55












  • 2




    Can you agree that $p_x=partial p/partial x$ and explain what $mathcalX$ here is?
    – Fakemistake
    Aug 14 at 11:14










  • @Fakemistake $p_x$ is just a constant. $mathcalX$ is just a set, the cardinality of which governs the degree of the polynomial whose monomials are of the form $(p_xy+(1-p_x))$.
    – Television
    Aug 14 at 11:16







  • 2




    The substitution $u = 1 - y$ simplifies the factors of the integrand to the form $1-p_x u$. The product can then be expanded as a polynomial in $u$, with coefficients expressed as elementary symmetric polynomials of the $p_i$. The integration of the expanded polynomial is straightforward.
    – Blue
    Aug 14 at 11:55







2




2




Can you agree that $p_x=partial p/partial x$ and explain what $mathcalX$ here is?
– Fakemistake
Aug 14 at 11:14




Can you agree that $p_x=partial p/partial x$ and explain what $mathcalX$ here is?
– Fakemistake
Aug 14 at 11:14












@Fakemistake $p_x$ is just a constant. $mathcalX$ is just a set, the cardinality of which governs the degree of the polynomial whose monomials are of the form $(p_xy+(1-p_x))$.
– Television
Aug 14 at 11:16





@Fakemistake $p_x$ is just a constant. $mathcalX$ is just a set, the cardinality of which governs the degree of the polynomial whose monomials are of the form $(p_xy+(1-p_x))$.
– Television
Aug 14 at 11:16





2




2




The substitution $u = 1 - y$ simplifies the factors of the integrand to the form $1-p_x u$. The product can then be expanded as a polynomial in $u$, with coefficients expressed as elementary symmetric polynomials of the $p_i$. The integration of the expanded polynomial is straightforward.
– Blue
Aug 14 at 11:55




The substitution $u = 1 - y$ simplifies the factors of the integrand to the form $1-p_x u$. The product can then be expanded as a polynomial in $u$, with coefficients expressed as elementary symmetric polynomials of the $p_i$. The integration of the expanded polynomial is straightforward.
– Blue
Aug 14 at 11:55










1 Answer
1






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I assume $|chi|<infty.$



If we are able to rewrite the product as follows
$$prod_xinchi(p_xy+(1-p_x))=sum_n=0^chia_ny^n$$
then the integral is very easy to compute and it results in
$$int_0^1prod_xinchi(p_xy+(1-p_x))dy=int_0^1sum_n=0^chia_ny^ndy=sum_n=0^chifraca_nn+1.$$
Now the terms $a_n$ are those where you multiply exactly $n$ $p_xy$ together and $|chi|-n$ terms of the form $(1-p_x)$ (look at the degreee). Thus
$$a_n=sum_=nprod_p_xin A p_xcdotprod_p_xnotin A(1-p_x)$$






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    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    1
    down vote



    accepted










    I assume $|chi|<infty.$



    If we are able to rewrite the product as follows
    $$prod_xinchi(p_xy+(1-p_x))=sum_n=0^chia_ny^n$$
    then the integral is very easy to compute and it results in
    $$int_0^1prod_xinchi(p_xy+(1-p_x))dy=int_0^1sum_n=0^chia_ny^ndy=sum_n=0^chifraca_nn+1.$$
    Now the terms $a_n$ are those where you multiply exactly $n$ $p_xy$ together and $|chi|-n$ terms of the form $(1-p_x)$ (look at the degreee). Thus
    $$a_n=sum_=nprod_p_xin A p_xcdotprod_p_xnotin A(1-p_x)$$






    share|cite|improve this answer
























      up vote
      1
      down vote



      accepted










      I assume $|chi|<infty.$



      If we are able to rewrite the product as follows
      $$prod_xinchi(p_xy+(1-p_x))=sum_n=0^chia_ny^n$$
      then the integral is very easy to compute and it results in
      $$int_0^1prod_xinchi(p_xy+(1-p_x))dy=int_0^1sum_n=0^chia_ny^ndy=sum_n=0^chifraca_nn+1.$$
      Now the terms $a_n$ are those where you multiply exactly $n$ $p_xy$ together and $|chi|-n$ terms of the form $(1-p_x)$ (look at the degreee). Thus
      $$a_n=sum_=nprod_p_xin A p_xcdotprod_p_xnotin A(1-p_x)$$






      share|cite|improve this answer






















        up vote
        1
        down vote



        accepted







        up vote
        1
        down vote



        accepted






        I assume $|chi|<infty.$



        If we are able to rewrite the product as follows
        $$prod_xinchi(p_xy+(1-p_x))=sum_n=0^chia_ny^n$$
        then the integral is very easy to compute and it results in
        $$int_0^1prod_xinchi(p_xy+(1-p_x))dy=int_0^1sum_n=0^chia_ny^ndy=sum_n=0^chifraca_nn+1.$$
        Now the terms $a_n$ are those where you multiply exactly $n$ $p_xy$ together and $|chi|-n$ terms of the form $(1-p_x)$ (look at the degreee). Thus
        $$a_n=sum_=nprod_p_xin A p_xcdotprod_p_xnotin A(1-p_x)$$






        share|cite|improve this answer












        I assume $|chi|<infty.$



        If we are able to rewrite the product as follows
        $$prod_xinchi(p_xy+(1-p_x))=sum_n=0^chia_ny^n$$
        then the integral is very easy to compute and it results in
        $$int_0^1prod_xinchi(p_xy+(1-p_x))dy=int_0^1sum_n=0^chia_ny^ndy=sum_n=0^chifraca_nn+1.$$
        Now the terms $a_n$ are those where you multiply exactly $n$ $p_xy$ together and $|chi|-n$ terms of the form $(1-p_x)$ (look at the degreee). Thus
        $$a_n=sum_=nprod_p_xin A p_xcdotprod_p_xnotin A(1-p_x)$$







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Aug 14 at 11:23









        b00n heT

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        8,08411430






















             

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