Spectral decomposition of an operator












2












$begingroup$


Given the operator:
$$begin{pmatrix}
i & 0 & - 4\
0 & - 3i & 0\
2 & 0 & - i
end{pmatrix}$$

Now $det(lambda1-A)=(z+3i)(z^2+9)=(z+3i)^2(z-3i)$,



I know a theorem that says that this three prepositions are equivalent:




  1. Eigenvectors of A form a basis,


  2. There are no spectral operators in spectral decomposition of A, $mathbb{E} $,


  3. R(z) has only poles of order one.


  4. A satisfies an algebric equation with all zeroes of order one ("simple roots").



Now to find the spectral representation I calculate the operator $R(z)=frac{1}{z1-A}$:
$$R(z)=begin{pmatrix}
frac{z+i} {(z+3i)(z-3i)} & 0 & frac{-4}{(z+3i)(z-3i)}\
0 & frac{1}{z+3i} & 0\
frac{2}{(z+3i)(z-3i)} & 0 & frac{z-i} {(z+3i)(z-3i)}
end{pmatrix} $$



And find that there are no spectral operators $mathbb{E} $ respecting 1 and 3 of the theorem, but the $det$ has not only zeroes of order one. How is this possible? How should I interpret the point 4 of the theorem?



Thanks you all










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$endgroup$

















    2












    $begingroup$


    Given the operator:
    $$begin{pmatrix}
    i & 0 & - 4\
    0 & - 3i & 0\
    2 & 0 & - i
    end{pmatrix}$$

    Now $det(lambda1-A)=(z+3i)(z^2+9)=(z+3i)^2(z-3i)$,



    I know a theorem that says that this three prepositions are equivalent:




    1. Eigenvectors of A form a basis,


    2. There are no spectral operators in spectral decomposition of A, $mathbb{E} $,


    3. R(z) has only poles of order one.


    4. A satisfies an algebric equation with all zeroes of order one ("simple roots").



    Now to find the spectral representation I calculate the operator $R(z)=frac{1}{z1-A}$:
    $$R(z)=begin{pmatrix}
    frac{z+i} {(z+3i)(z-3i)} & 0 & frac{-4}{(z+3i)(z-3i)}\
    0 & frac{1}{z+3i} & 0\
    frac{2}{(z+3i)(z-3i)} & 0 & frac{z-i} {(z+3i)(z-3i)}
    end{pmatrix} $$



    And find that there are no spectral operators $mathbb{E} $ respecting 1 and 3 of the theorem, but the $det$ has not only zeroes of order one. How is this possible? How should I interpret the point 4 of the theorem?



    Thanks you all










    share|cite|improve this question











    $endgroup$















      2












      2








      2





      $begingroup$


      Given the operator:
      $$begin{pmatrix}
      i & 0 & - 4\
      0 & - 3i & 0\
      2 & 0 & - i
      end{pmatrix}$$

      Now $det(lambda1-A)=(z+3i)(z^2+9)=(z+3i)^2(z-3i)$,



      I know a theorem that says that this three prepositions are equivalent:




      1. Eigenvectors of A form a basis,


      2. There are no spectral operators in spectral decomposition of A, $mathbb{E} $,


      3. R(z) has only poles of order one.


      4. A satisfies an algebric equation with all zeroes of order one ("simple roots").



      Now to find the spectral representation I calculate the operator $R(z)=frac{1}{z1-A}$:
      $$R(z)=begin{pmatrix}
      frac{z+i} {(z+3i)(z-3i)} & 0 & frac{-4}{(z+3i)(z-3i)}\
      0 & frac{1}{z+3i} & 0\
      frac{2}{(z+3i)(z-3i)} & 0 & frac{z-i} {(z+3i)(z-3i)}
      end{pmatrix} $$



      And find that there are no spectral operators $mathbb{E} $ respecting 1 and 3 of the theorem, but the $det$ has not only zeroes of order one. How is this possible? How should I interpret the point 4 of the theorem?



      Thanks you all










      share|cite|improve this question











      $endgroup$




      Given the operator:
      $$begin{pmatrix}
      i & 0 & - 4\
      0 & - 3i & 0\
      2 & 0 & - i
      end{pmatrix}$$

      Now $det(lambda1-A)=(z+3i)(z^2+9)=(z+3i)^2(z-3i)$,



      I know a theorem that says that this three prepositions are equivalent:




      1. Eigenvectors of A form a basis,


      2. There are no spectral operators in spectral decomposition of A, $mathbb{E} $,


      3. R(z) has only poles of order one.


      4. A satisfies an algebric equation with all zeroes of order one ("simple roots").



      Now to find the spectral representation I calculate the operator $R(z)=frac{1}{z1-A}$:
      $$R(z)=begin{pmatrix}
      frac{z+i} {(z+3i)(z-3i)} & 0 & frac{-4}{(z+3i)(z-3i)}\
      0 & frac{1}{z+3i} & 0\
      frac{2}{(z+3i)(z-3i)} & 0 & frac{z-i} {(z+3i)(z-3i)}
      end{pmatrix} $$



      And find that there are no spectral operators $mathbb{E} $ respecting 1 and 3 of the theorem, but the $det$ has not only zeroes of order one. How is this possible? How should I interpret the point 4 of the theorem?



      Thanks you all







      operator-theory determinant diagonalization spectra






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      edited Jan 3 at 10:46







      pter26

















      asked Jan 3 at 10:09









      pter26pter26

      317111




      317111






















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