If $L,A in m(n,n)$ on $R$, when exists L for which $(L^{T}AL)$ is a diagonal block matrix?












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If $L,A in m(n,n)$ on $R$, when exists L for which $(L^{T}AL)$ is a diagonal block matrix? Of course if $A$ is symmetrycal then $L$ exists and is a matrix of its eigenvectors, but I don't want to consider this case.










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  • $begingroup$
    You are going to need a stronger condition to make this interesting, because every $ntimes n$ matrix is a diagonal block matrix with one $ntimes n$ block.
    $endgroup$
    – Aaron
    Dec 16 '18 at 13:18










  • $begingroup$
    It was implicit that the numbers of blocks must be more than one. @Aaron
    $endgroup$
    – Landau
    Dec 16 '18 at 13:24
















0












$begingroup$


If $L,A in m(n,n)$ on $R$, when exists L for which $(L^{T}AL)$ is a diagonal block matrix? Of course if $A$ is symmetrycal then $L$ exists and is a matrix of its eigenvectors, but I don't want to consider this case.










share|cite|improve this question









$endgroup$












  • $begingroup$
    You are going to need a stronger condition to make this interesting, because every $ntimes n$ matrix is a diagonal block matrix with one $ntimes n$ block.
    $endgroup$
    – Aaron
    Dec 16 '18 at 13:18










  • $begingroup$
    It was implicit that the numbers of blocks must be more than one. @Aaron
    $endgroup$
    – Landau
    Dec 16 '18 at 13:24














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0








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$begingroup$


If $L,A in m(n,n)$ on $R$, when exists L for which $(L^{T}AL)$ is a diagonal block matrix? Of course if $A$ is symmetrycal then $L$ exists and is a matrix of its eigenvectors, but I don't want to consider this case.










share|cite|improve this question









$endgroup$




If $L,A in m(n,n)$ on $R$, when exists L for which $(L^{T}AL)$ is a diagonal block matrix? Of course if $A$ is symmetrycal then $L$ exists and is a matrix of its eigenvectors, but I don't want to consider this case.







linear-algebra






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asked Dec 16 '18 at 13:01









LandauLandau

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447












  • $begingroup$
    You are going to need a stronger condition to make this interesting, because every $ntimes n$ matrix is a diagonal block matrix with one $ntimes n$ block.
    $endgroup$
    – Aaron
    Dec 16 '18 at 13:18










  • $begingroup$
    It was implicit that the numbers of blocks must be more than one. @Aaron
    $endgroup$
    – Landau
    Dec 16 '18 at 13:24


















  • $begingroup$
    You are going to need a stronger condition to make this interesting, because every $ntimes n$ matrix is a diagonal block matrix with one $ntimes n$ block.
    $endgroup$
    – Aaron
    Dec 16 '18 at 13:18










  • $begingroup$
    It was implicit that the numbers of blocks must be more than one. @Aaron
    $endgroup$
    – Landau
    Dec 16 '18 at 13:24
















$begingroup$
You are going to need a stronger condition to make this interesting, because every $ntimes n$ matrix is a diagonal block matrix with one $ntimes n$ block.
$endgroup$
– Aaron
Dec 16 '18 at 13:18




$begingroup$
You are going to need a stronger condition to make this interesting, because every $ntimes n$ matrix is a diagonal block matrix with one $ntimes n$ block.
$endgroup$
– Aaron
Dec 16 '18 at 13:18












$begingroup$
It was implicit that the numbers of blocks must be more than one. @Aaron
$endgroup$
– Landau
Dec 16 '18 at 13:24




$begingroup$
It was implicit that the numbers of blocks must be more than one. @Aaron
$endgroup$
– Landau
Dec 16 '18 at 13:24










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