Characterization of diagonal matrices reducing rank












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Given full rank matrix $A$. I am looking for a characterization of all diagonal matrices $D$ with
$$
det(D - A) = 0
$$

This set of rank-reducing matrices is then somehow a superset to the $lambda I$ used in the eigenvalue equation.










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    1












    $begingroup$


    Given full rank matrix $A$. I am looking for a characterization of all diagonal matrices $D$ with
    $$
    det(D - A) = 0
    $$

    This set of rank-reducing matrices is then somehow a superset to the $lambda I$ used in the eigenvalue equation.










    share|cite|improve this question









    $endgroup$















      1












      1








      1





      $begingroup$


      Given full rank matrix $A$. I am looking for a characterization of all diagonal matrices $D$ with
      $$
      det(D - A) = 0
      $$

      This set of rank-reducing matrices is then somehow a superset to the $lambda I$ used in the eigenvalue equation.










      share|cite|improve this question









      $endgroup$




      Given full rank matrix $A$. I am looking for a characterization of all diagonal matrices $D$ with
      $$
      det(D - A) = 0
      $$

      This set of rank-reducing matrices is then somehow a superset to the $lambda I$ used in the eigenvalue equation.







      linear-algebra






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      asked Jan 21 at 21:31









      Sebastian SchlechtSebastian Schlecht

      23018




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          $begingroup$

          Actually there are a lot of such diagonal matrices. Notice that for any choice of the first $n-1$ elements of the diagonal, there always exists a unique $n$-th entry such that $det(A-D)=0$.






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            $begingroup$

            Actually there are a lot of such diagonal matrices. Notice that for any choice of the first $n-1$ elements of the diagonal, there always exists a unique $n$-th entry such that $det(A-D)=0$.






            share|cite|improve this answer









            $endgroup$


















              0












              $begingroup$

              Actually there are a lot of such diagonal matrices. Notice that for any choice of the first $n-1$ elements of the diagonal, there always exists a unique $n$-th entry such that $det(A-D)=0$.






              share|cite|improve this answer









              $endgroup$
















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                0





                $begingroup$

                Actually there are a lot of such diagonal matrices. Notice that for any choice of the first $n-1$ elements of the diagonal, there always exists a unique $n$-th entry such that $det(A-D)=0$.






                share|cite|improve this answer









                $endgroup$



                Actually there are a lot of such diagonal matrices. Notice that for any choice of the first $n-1$ elements of the diagonal, there always exists a unique $n$-th entry such that $det(A-D)=0$.







                share|cite|improve this answer












                share|cite|improve this answer



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                answered Jan 21 at 21:43









                ExoddExodd

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