time-shift in partial differential equation of density function












1












$begingroup$


I am reading the following paper:



http://www.nacad.ufrj.br/~amit/lyapdual.pdf (see Appendix A. Lemma A.1. proof)



enter image description here



My understanding of a few notations are:





  1. $rho_t(z)$: the density function around initial point $z$ at time $t$


  2. $phi_t(z)$: the solution $x(t)$ of $dot{x}(t)=f(x(t))$ with $x(0)=z$. This is also called phase flow.


Note that $$rho_t(z)=rho(phi_t(z))|(partialphi(t)/partial z)(z)|$$



this is coming from the evolution of density with time. The term $|(partialphi(t)/partial z)(z)|$ is actually the Jacobian. Also note that $$dot{phi}_t(z) = f(z) = f$$





My question is



enter image description here




  1. How can we change $t=tau$ to $h=0$.

  2. Why did the author add $rho_h$, the $h$ parameter?










share|cite|improve this question











$endgroup$

















    1












    $begingroup$


    I am reading the following paper:



    http://www.nacad.ufrj.br/~amit/lyapdual.pdf (see Appendix A. Lemma A.1. proof)



    enter image description here



    My understanding of a few notations are:





    1. $rho_t(z)$: the density function around initial point $z$ at time $t$


    2. $phi_t(z)$: the solution $x(t)$ of $dot{x}(t)=f(x(t))$ with $x(0)=z$. This is also called phase flow.


    Note that $$rho_t(z)=rho(phi_t(z))|(partialphi(t)/partial z)(z)|$$



    this is coming from the evolution of density with time. The term $|(partialphi(t)/partial z)(z)|$ is actually the Jacobian. Also note that $$dot{phi}_t(z) = f(z) = f$$





    My question is



    enter image description here




    1. How can we change $t=tau$ to $h=0$.

    2. Why did the author add $rho_h$, the $h$ parameter?










    share|cite|improve this question











    $endgroup$















      1












      1








      1





      $begingroup$


      I am reading the following paper:



      http://www.nacad.ufrj.br/~amit/lyapdual.pdf (see Appendix A. Lemma A.1. proof)



      enter image description here



      My understanding of a few notations are:





      1. $rho_t(z)$: the density function around initial point $z$ at time $t$


      2. $phi_t(z)$: the solution $x(t)$ of $dot{x}(t)=f(x(t))$ with $x(0)=z$. This is also called phase flow.


      Note that $$rho_t(z)=rho(phi_t(z))|(partialphi(t)/partial z)(z)|$$



      this is coming from the evolution of density with time. The term $|(partialphi(t)/partial z)(z)|$ is actually the Jacobian. Also note that $$dot{phi}_t(z) = f(z) = f$$





      My question is



      enter image description here




      1. How can we change $t=tau$ to $h=0$.

      2. Why did the author add $rho_h$, the $h$ parameter?










      share|cite|improve this question











      $endgroup$




      I am reading the following paper:



      http://www.nacad.ufrj.br/~amit/lyapdual.pdf (see Appendix A. Lemma A.1. proof)



      enter image description here



      My understanding of a few notations are:





      1. $rho_t(z)$: the density function around initial point $z$ at time $t$


      2. $phi_t(z)$: the solution $x(t)$ of $dot{x}(t)=f(x(t))$ with $x(0)=z$. This is also called phase flow.


      Note that $$rho_t(z)=rho(phi_t(z))|(partialphi(t)/partial z)(z)|$$



      this is coming from the evolution of density with time. The term $|(partialphi(t)/partial z)(z)|$ is actually the Jacobian. Also note that $$dot{phi}_t(z) = f(z) = f$$





      My question is



      enter image description here




      1. How can we change $t=tau$ to $h=0$.

      2. Why did the author add $rho_h$, the $h$ parameter?







      derivatives partial-derivative dynamical-systems






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Dec 30 '18 at 4:45







      sleeve chen

















      asked Dec 30 '18 at 0:12









      sleeve chensleeve chen

      3,14041853




      3,14041853






















          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%2f3056392%2ftime-shift-in-partial-differential-equation-of-density-function%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%2f3056392%2ftime-shift-in-partial-differential-equation-of-density-function%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

          Bressuire

          Cabo Verde

          Gyllenstierna