Solving OR bounding sums of solutions to certain linear diophantine equations

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(This question arose during group work on classifying modular tensor categories.)



Let $p$ and $q$ be two distinct primes. We seek integral solutions $lbrace x_i,j rbrace$ to the equation



beginalign
0 = sum_i=0^i=m sum_j=m-i^j=m p^i q^j x_i,j
endalign
subject to the requirements



beginalign
x_m,m=-1, \ p nmid x_i,j, \ q nmid x_i,j.
endalign



For example, when $p=5$, $q=7$, and $m=3$, we want to find integral solutions to the equation



beginalign
5^3 7^3 = 5^1 7^2 x_1,2 + 5^2 7^1 x_2,1 + 5^3 7^0 x_3,0 + 5^0 7^3 x_0,3 + 5^2 7^2 x_2,2 + 5^3 7^1 x_3,1 + 5^1 7^3 x_1,3 + 5^3 7^2 x_3,2 + 5^2 7^3 x_2,3
endalign



such that none of the non-zero $x_i,j$ are divisible by 5 or 7. (We do allow $x_i,j$ to equal $0$.)



Question 1. What algebraic geometry would be necessary to attack this problem? It seems related to "finding integral points," so it could be much more difficult than I appreciate.



Question 2. If determining integral solutions is too hard: Is there a way we could at least give a bound for the sum of all the $x_i,j$ in terms of $m$? That is, can we say



beginalign
sum_i=0^i=m sum_j=m-i^j=m x_i,j , < , f(m)
endalign



for some function $f(m)$ that doesn't grow too fast?







share|cite|improve this question

























    up vote
    1
    down vote

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    (This question arose during group work on classifying modular tensor categories.)



    Let $p$ and $q$ be two distinct primes. We seek integral solutions $lbrace x_i,j rbrace$ to the equation



    beginalign
    0 = sum_i=0^i=m sum_j=m-i^j=m p^i q^j x_i,j
    endalign
    subject to the requirements



    beginalign
    x_m,m=-1, \ p nmid x_i,j, \ q nmid x_i,j.
    endalign



    For example, when $p=5$, $q=7$, and $m=3$, we want to find integral solutions to the equation



    beginalign
    5^3 7^3 = 5^1 7^2 x_1,2 + 5^2 7^1 x_2,1 + 5^3 7^0 x_3,0 + 5^0 7^3 x_0,3 + 5^2 7^2 x_2,2 + 5^3 7^1 x_3,1 + 5^1 7^3 x_1,3 + 5^3 7^2 x_3,2 + 5^2 7^3 x_2,3
    endalign



    such that none of the non-zero $x_i,j$ are divisible by 5 or 7. (We do allow $x_i,j$ to equal $0$.)



    Question 1. What algebraic geometry would be necessary to attack this problem? It seems related to "finding integral points," so it could be much more difficult than I appreciate.



    Question 2. If determining integral solutions is too hard: Is there a way we could at least give a bound for the sum of all the $x_i,j$ in terms of $m$? That is, can we say



    beginalign
    sum_i=0^i=m sum_j=m-i^j=m x_i,j , < , f(m)
    endalign



    for some function $f(m)$ that doesn't grow too fast?







    share|cite|improve this question























      up vote
      1
      down vote

      favorite









      up vote
      1
      down vote

      favorite











      (This question arose during group work on classifying modular tensor categories.)



      Let $p$ and $q$ be two distinct primes. We seek integral solutions $lbrace x_i,j rbrace$ to the equation



      beginalign
      0 = sum_i=0^i=m sum_j=m-i^j=m p^i q^j x_i,j
      endalign
      subject to the requirements



      beginalign
      x_m,m=-1, \ p nmid x_i,j, \ q nmid x_i,j.
      endalign



      For example, when $p=5$, $q=7$, and $m=3$, we want to find integral solutions to the equation



      beginalign
      5^3 7^3 = 5^1 7^2 x_1,2 + 5^2 7^1 x_2,1 + 5^3 7^0 x_3,0 + 5^0 7^3 x_0,3 + 5^2 7^2 x_2,2 + 5^3 7^1 x_3,1 + 5^1 7^3 x_1,3 + 5^3 7^2 x_3,2 + 5^2 7^3 x_2,3
      endalign



      such that none of the non-zero $x_i,j$ are divisible by 5 or 7. (We do allow $x_i,j$ to equal $0$.)



      Question 1. What algebraic geometry would be necessary to attack this problem? It seems related to "finding integral points," so it could be much more difficult than I appreciate.



      Question 2. If determining integral solutions is too hard: Is there a way we could at least give a bound for the sum of all the $x_i,j$ in terms of $m$? That is, can we say



      beginalign
      sum_i=0^i=m sum_j=m-i^j=m x_i,j , < , f(m)
      endalign



      for some function $f(m)$ that doesn't grow too fast?







      share|cite|improve this question













      (This question arose during group work on classifying modular tensor categories.)



      Let $p$ and $q$ be two distinct primes. We seek integral solutions $lbrace x_i,j rbrace$ to the equation



      beginalign
      0 = sum_i=0^i=m sum_j=m-i^j=m p^i q^j x_i,j
      endalign
      subject to the requirements



      beginalign
      x_m,m=-1, \ p nmid x_i,j, \ q nmid x_i,j.
      endalign



      For example, when $p=5$, $q=7$, and $m=3$, we want to find integral solutions to the equation



      beginalign
      5^3 7^3 = 5^1 7^2 x_1,2 + 5^2 7^1 x_2,1 + 5^3 7^0 x_3,0 + 5^0 7^3 x_0,3 + 5^2 7^2 x_2,2 + 5^3 7^1 x_3,1 + 5^1 7^3 x_1,3 + 5^3 7^2 x_3,2 + 5^2 7^3 x_2,3
      endalign



      such that none of the non-zero $x_i,j$ are divisible by 5 or 7. (We do allow $x_i,j$ to equal $0$.)



      Question 1. What algebraic geometry would be necessary to attack this problem? It seems related to "finding integral points," so it could be much more difficult than I appreciate.



      Question 2. If determining integral solutions is too hard: Is there a way we could at least give a bound for the sum of all the $x_i,j$ in terms of $m$? That is, can we say



      beginalign
      sum_i=0^i=m sum_j=m-i^j=m x_i,j , < , f(m)
      endalign



      for some function $f(m)$ that doesn't grow too fast?









      share|cite|improve this question












      share|cite|improve this question




      share|cite|improve this question








      edited Jul 20 at 20:19
























      asked Jul 20 at 16:36









      L.C. Ruth

      513




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