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












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
















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














0












0








0


1



$begingroup$


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






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked Dec 16 '18 at 13:01









LandauLandau

447




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










0






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',
autoActivateHeartbeat: false,
convertImagesToLinks: true,
noModals: true,
showLowRepImageUploadWarning: true,
reputationToPostImages: 10,
bindNavPrevention: true,
postfix: "",
imageUploader: {
brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
allowUrls: true
},
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%2f3042586%2fif-l-a-in-mn-n-on-r-when-exists-l-for-which-ltal-is-a-diagonal-bl%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown

























0






active

oldest

votes








0






active

oldest

votes









active

oldest

votes






active

oldest

votes
















draft saved

draft discarded




















































Thanks for contributing an answer to Mathematics Stack Exchange!


  • Please be sure to answer the question. Provide details and share your research!

But avoid



  • Asking for help, clarification, or responding to other answers.

  • Making statements based on opinion; back them up with references or personal experience.


Use MathJax to format equations. MathJax reference.


To learn more, see our tips on writing great answers.




draft saved


draft discarded














StackExchange.ready(
function () {
StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3042586%2fif-l-a-in-mn-n-on-r-when-exists-l-for-which-ltal-is-a-diagonal-bl%23new-answer', 'question_page');
}
);

Post as a guest















Required, but never shown





















































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown

































Required, but never shown














Required, but never shown












Required, but never shown







Required, but never shown







Popular posts from this blog

Wiesbaden

To store a contact into the json file from server.js file using a class in NodeJS

Marschland