General techniques for proving coefficients of a multinomial are all positive

The name of the pictureThe name of the pictureThe name of the pictureClash Royale CLAN TAG#URR8PPP











up vote
4
down vote

favorite
1












I have encountered a problem in my research where I need to prove that all the coefficients of a certain multinomial of the form $R_k(mathbfx, mathbfy) = fracP_k(mathbfx, mathbfy)Q_k(mathbfx, mathbfy)$ are positive, where $mathbfx = (x_1,dots,x_n)$, and $mathbfy = (y_1,dots,y_n)$. It is known that $P_k$ is divisible by $Q_k$. Here $k$ can be any positive integer, i.e. I need to prove the statement for each value of $k$. We also know the following about $R_k$:



  • $R_k$ is a homogeneous multinomial of degree $n(n-1)(k-1)$,

  • $R_k$ is symmetric w.r.t. $mathbfx$, and w.r.t. $mathbfy$ separately,

  • $R_k(mathbfx, mathbfy) = R_k(mathbfy, mathbfx)$.

I should state that I have no prior background in algebraic geometry, which I suspect might be the kind of tools I need for this problem. So my question to the community is whether anyone has seen similar problems before, or knows of general techniques that are used to solve similar problems, and point me to them. My search so far has been quite futile in trying to find techniques to solve my problem.







share|cite|improve this question


























    up vote
    4
    down vote

    favorite
    1












    I have encountered a problem in my research where I need to prove that all the coefficients of a certain multinomial of the form $R_k(mathbfx, mathbfy) = fracP_k(mathbfx, mathbfy)Q_k(mathbfx, mathbfy)$ are positive, where $mathbfx = (x_1,dots,x_n)$, and $mathbfy = (y_1,dots,y_n)$. It is known that $P_k$ is divisible by $Q_k$. Here $k$ can be any positive integer, i.e. I need to prove the statement for each value of $k$. We also know the following about $R_k$:



    • $R_k$ is a homogeneous multinomial of degree $n(n-1)(k-1)$,

    • $R_k$ is symmetric w.r.t. $mathbfx$, and w.r.t. $mathbfy$ separately,

    • $R_k(mathbfx, mathbfy) = R_k(mathbfy, mathbfx)$.

    I should state that I have no prior background in algebraic geometry, which I suspect might be the kind of tools I need for this problem. So my question to the community is whether anyone has seen similar problems before, or knows of general techniques that are used to solve similar problems, and point me to them. My search so far has been quite futile in trying to find techniques to solve my problem.







    share|cite|improve this question
























      up vote
      4
      down vote

      favorite
      1









      up vote
      4
      down vote

      favorite
      1






      1





      I have encountered a problem in my research where I need to prove that all the coefficients of a certain multinomial of the form $R_k(mathbfx, mathbfy) = fracP_k(mathbfx, mathbfy)Q_k(mathbfx, mathbfy)$ are positive, where $mathbfx = (x_1,dots,x_n)$, and $mathbfy = (y_1,dots,y_n)$. It is known that $P_k$ is divisible by $Q_k$. Here $k$ can be any positive integer, i.e. I need to prove the statement for each value of $k$. We also know the following about $R_k$:



      • $R_k$ is a homogeneous multinomial of degree $n(n-1)(k-1)$,

      • $R_k$ is symmetric w.r.t. $mathbfx$, and w.r.t. $mathbfy$ separately,

      • $R_k(mathbfx, mathbfy) = R_k(mathbfy, mathbfx)$.

      I should state that I have no prior background in algebraic geometry, which I suspect might be the kind of tools I need for this problem. So my question to the community is whether anyone has seen similar problems before, or knows of general techniques that are used to solve similar problems, and point me to them. My search so far has been quite futile in trying to find techniques to solve my problem.







      share|cite|improve this question














      I have encountered a problem in my research where I need to prove that all the coefficients of a certain multinomial of the form $R_k(mathbfx, mathbfy) = fracP_k(mathbfx, mathbfy)Q_k(mathbfx, mathbfy)$ are positive, where $mathbfx = (x_1,dots,x_n)$, and $mathbfy = (y_1,dots,y_n)$. It is known that $P_k$ is divisible by $Q_k$. Here $k$ can be any positive integer, i.e. I need to prove the statement for each value of $k$. We also know the following about $R_k$:



      • $R_k$ is a homogeneous multinomial of degree $n(n-1)(k-1)$,

      • $R_k$ is symmetric w.r.t. $mathbfx$, and w.r.t. $mathbfy$ separately,

      • $R_k(mathbfx, mathbfy) = R_k(mathbfy, mathbfx)$.

      I should state that I have no prior background in algebraic geometry, which I suspect might be the kind of tools I need for this problem. So my question to the community is whether anyone has seen similar problems before, or knows of general techniques that are used to solve similar problems, and point me to them. My search so far has been quite futile in trying to find techniques to solve my problem.









      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Aug 26 at 18:12









      Jendrik Stelzner

      7,57221037




      7,57221037










      asked Aug 24 at 7:43









      Rahul Sarkar

      365




      365

























          active

          oldest

          votes











          Your Answer




          StackExchange.ifUsing("editor", function ()
          return StackExchange.using("mathjaxEditing", function ()
          StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix)
          StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
          );
          );
          , "mathjax-editing");

          StackExchange.ready(function()
          var channelOptions =
          tags: "".split(" "),
          id: "69"
          ;
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function()
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled)
          StackExchange.using("snippets", function()
          createEditor();
          );

          else
          createEditor();

          );

          function createEditor()
          StackExchange.prepareEditor(
          heartbeatType: 'answer',
          convertImagesToLinks: true,
          noModals: false,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: 10,
          bindNavPrevention: true,
          postfix: "",
          noCode: true, onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          );



          );













           

          draft saved


          draft discarded


















          StackExchange.ready(
          function ()
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2892878%2fgeneral-techniques-for-proving-coefficients-of-a-multinomial-are-all-positive%23new-answer', 'question_page');

          );

          Post as a guest



































          active

          oldest

          votes













          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes















           

          draft saved


          draft discarded















































           


          draft saved


          draft discarded














          StackExchange.ready(
          function ()
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f2892878%2fgeneral-techniques-for-proving-coefficients-of-a-multinomial-are-all-positive%23new-answer', 'question_page');

          );

          Post as a guest













































































          這個網誌中的熱門文章

          How to combine Bézier curves to a surface?

          Mutual Information Always Non-negative

          Why am i infinitely getting the same tweet with the Twitter Search API?