If real matrices $A,B$ have the same ch. polynomial and rank, and rk$(A-lambda I)= text{rk}(B-lambda I)$ for...












2












$begingroup$


Some time ago I had a linear algebra private lesson, and rereading some notes of the professor, I've found




If two real matrices $A,B$ have the same characteristic polynomial and rank, and satisfy $ operatorname{rk}(A-lambda I)= operatorname{rk}(B-lambda I)$ for each eigenvalue, then they are similar




but with no proof. Is this true? And if so, how would one prove it? What I do know is that having the same characteristic polynomial and rank is not enough, but I'm not sure why the additional condition would fill the gap










share|cite|improve this question











$endgroup$

















    2












    $begingroup$


    Some time ago I had a linear algebra private lesson, and rereading some notes of the professor, I've found




    If two real matrices $A,B$ have the same characteristic polynomial and rank, and satisfy $ operatorname{rk}(A-lambda I)= operatorname{rk}(B-lambda I)$ for each eigenvalue, then they are similar




    but with no proof. Is this true? And if so, how would one prove it? What I do know is that having the same characteristic polynomial and rank is not enough, but I'm not sure why the additional condition would fill the gap










    share|cite|improve this question











    $endgroup$















      2












      2








      2





      $begingroup$


      Some time ago I had a linear algebra private lesson, and rereading some notes of the professor, I've found




      If two real matrices $A,B$ have the same characteristic polynomial and rank, and satisfy $ operatorname{rk}(A-lambda I)= operatorname{rk}(B-lambda I)$ for each eigenvalue, then they are similar




      but with no proof. Is this true? And if so, how would one prove it? What I do know is that having the same characteristic polynomial and rank is not enough, but I'm not sure why the additional condition would fill the gap










      share|cite|improve this question











      $endgroup$




      Some time ago I had a linear algebra private lesson, and rereading some notes of the professor, I've found




      If two real matrices $A,B$ have the same characteristic polynomial and rank, and satisfy $ operatorname{rk}(A-lambda I)= operatorname{rk}(B-lambda I)$ for each eigenvalue, then they are similar




      but with no proof. Is this true? And if so, how would one prove it? What I do know is that having the same characteristic polynomial and rank is not enough, but I'm not sure why the additional condition would fill the gap







      linear-algebra matrices eigenvalues-eigenvectors determinant matrix-rank






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 19 at 9:38









      Bernard

      121k740116




      121k740116










      asked Jan 19 at 8:18









      LearnerLearner

      17510




      17510






















          1 Answer
          1






          active

          oldest

          votes


















          1












          $begingroup$

          How about
          $$pmatrix{0&1&0&0\0&0&0&0\0&0&0&1\0&0&0&0}$$
          and
          $$pmatrix{0&1&0&0\0&0&1&0\0&0&0&0\0&0&0&0}?$$






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Yes then I saw it doesn't matter if the eigenvalues are non-zero haha, I just thought maybe it was "my fault", not the prof's mistake. Thanks!
            $endgroup$
            – Learner
            Jan 19 at 8:26













          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%2f3079105%2fif-real-matrices-a-b-have-the-same-ch-polynomial-and-rank-and-rka-lambda%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          1












          $begingroup$

          How about
          $$pmatrix{0&1&0&0\0&0&0&0\0&0&0&1\0&0&0&0}$$
          and
          $$pmatrix{0&1&0&0\0&0&1&0\0&0&0&0\0&0&0&0}?$$






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Yes then I saw it doesn't matter if the eigenvalues are non-zero haha, I just thought maybe it was "my fault", not the prof's mistake. Thanks!
            $endgroup$
            – Learner
            Jan 19 at 8:26


















          1












          $begingroup$

          How about
          $$pmatrix{0&1&0&0\0&0&0&0\0&0&0&1\0&0&0&0}$$
          and
          $$pmatrix{0&1&0&0\0&0&1&0\0&0&0&0\0&0&0&0}?$$






          share|cite|improve this answer









          $endgroup$













          • $begingroup$
            Yes then I saw it doesn't matter if the eigenvalues are non-zero haha, I just thought maybe it was "my fault", not the prof's mistake. Thanks!
            $endgroup$
            – Learner
            Jan 19 at 8:26
















          1












          1








          1





          $begingroup$

          How about
          $$pmatrix{0&1&0&0\0&0&0&0\0&0&0&1\0&0&0&0}$$
          and
          $$pmatrix{0&1&0&0\0&0&1&0\0&0&0&0\0&0&0&0}?$$






          share|cite|improve this answer









          $endgroup$



          How about
          $$pmatrix{0&1&0&0\0&0&0&0\0&0&0&1\0&0&0&0}$$
          and
          $$pmatrix{0&1&0&0\0&0&1&0\0&0&0&0\0&0&0&0}?$$







          share|cite|improve this answer












          share|cite|improve this answer



          share|cite|improve this answer










          answered Jan 19 at 8:21









          Lord Shark the UnknownLord Shark the Unknown

          105k1160133




          105k1160133












          • $begingroup$
            Yes then I saw it doesn't matter if the eigenvalues are non-zero haha, I just thought maybe it was "my fault", not the prof's mistake. Thanks!
            $endgroup$
            – Learner
            Jan 19 at 8:26




















          • $begingroup$
            Yes then I saw it doesn't matter if the eigenvalues are non-zero haha, I just thought maybe it was "my fault", not the prof's mistake. Thanks!
            $endgroup$
            – Learner
            Jan 19 at 8:26


















          $begingroup$
          Yes then I saw it doesn't matter if the eigenvalues are non-zero haha, I just thought maybe it was "my fault", not the prof's mistake. Thanks!
          $endgroup$
          – Learner
          Jan 19 at 8:26






          $begingroup$
          Yes then I saw it doesn't matter if the eigenvalues are non-zero haha, I just thought maybe it was "my fault", not the prof's mistake. Thanks!
          $endgroup$
          – Learner
          Jan 19 at 8:26




















          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%2f3079105%2fif-real-matrices-a-b-have-the-same-ch-polynomial-and-rank-and-rka-lambda%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

          MongoDB - Not Authorized To Execute Command

          How to fix TextFormField cause rebuild widget in Flutter

          in spring boot 2.1 many test slices are not allowed anymore due to multiple @BootstrapWith