Fourth-order Sturm Liouville form












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$begingroup$


A fourth-order ODE in the form
begin{align}
[p(x)f''(x)]'' - [q(x)f'(x)]' + s(x) f(x) = lambda r(x) f(x),
end{align}

is in a fourth-order Sturm Liouville form. In the simpler second-order problem, I know that every second-order ODE can be written in the second-order Sturm Liouville form.



Is this true for any fourth-order ODE? Suppose I have
begin{align}
sum_{i=0}^4a_i(x) f^{(i)}(x) = lambda r(x) f(x),
end{align}

is it possible to always write this in the form above?










share|cite|improve this question











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    0












    $begingroup$


    A fourth-order ODE in the form
    begin{align}
    [p(x)f''(x)]'' - [q(x)f'(x)]' + s(x) f(x) = lambda r(x) f(x),
    end{align}

    is in a fourth-order Sturm Liouville form. In the simpler second-order problem, I know that every second-order ODE can be written in the second-order Sturm Liouville form.



    Is this true for any fourth-order ODE? Suppose I have
    begin{align}
    sum_{i=0}^4a_i(x) f^{(i)}(x) = lambda r(x) f(x),
    end{align}

    is it possible to always write this in the form above?










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      A fourth-order ODE in the form
      begin{align}
      [p(x)f''(x)]'' - [q(x)f'(x)]' + s(x) f(x) = lambda r(x) f(x),
      end{align}

      is in a fourth-order Sturm Liouville form. In the simpler second-order problem, I know that every second-order ODE can be written in the second-order Sturm Liouville form.



      Is this true for any fourth-order ODE? Suppose I have
      begin{align}
      sum_{i=0}^4a_i(x) f^{(i)}(x) = lambda r(x) f(x),
      end{align}

      is it possible to always write this in the form above?










      share|cite|improve this question











      $endgroup$




      A fourth-order ODE in the form
      begin{align}
      [p(x)f''(x)]'' - [q(x)f'(x)]' + s(x) f(x) = lambda r(x) f(x),
      end{align}

      is in a fourth-order Sturm Liouville form. In the simpler second-order problem, I know that every second-order ODE can be written in the second-order Sturm Liouville form.



      Is this true for any fourth-order ODE? Suppose I have
      begin{align}
      sum_{i=0}^4a_i(x) f^{(i)}(x) = lambda r(x) f(x),
      end{align}

      is it possible to always write this in the form above?







      sturm-liouville






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 9 at 16:07







      K L

















      asked Jan 9 at 15:55









      K LK L

      436




      436






















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