Change of Variable formula for a non-differentiable mapping.












7














Let $Omega subset Bbb R^n$. For a diffeomorphism (or merely a differentiable bijection) $varphi:Omega to varphi(Omega)$, we have the formula
$$
int_{Omega} fcircvarphi^{-1}(x), dx = int_{varphi^{-1}(Omega)} f(y)|Dvarphi(y)| ,dy.
$$




How much can we generalize the class in which $varphi$ is allowed to lie in? Is it enough that we have, says, a bijection $varphiin W_{text{loc}}^{1,infty}(Omega ;Bbb R^n)$ or even $varphiin W_{text{loc}}^{1,1}(Omega ;Bbb R^n)$?




How much does the result depends on the domain $Omega$? Is there a big difference between a compact and an open domain? Does the regularity of the boundary $partial Omega$ play any role?



I'd also appreciate if you have a good reference to this kind of result so that I can read further into this interesting issue. Happy New Year to all of you.










share|cite|improve this question





























    7














    Let $Omega subset Bbb R^n$. For a diffeomorphism (or merely a differentiable bijection) $varphi:Omega to varphi(Omega)$, we have the formula
    $$
    int_{Omega} fcircvarphi^{-1}(x), dx = int_{varphi^{-1}(Omega)} f(y)|Dvarphi(y)| ,dy.
    $$




    How much can we generalize the class in which $varphi$ is allowed to lie in? Is it enough that we have, says, a bijection $varphiin W_{text{loc}}^{1,infty}(Omega ;Bbb R^n)$ or even $varphiin W_{text{loc}}^{1,1}(Omega ;Bbb R^n)$?




    How much does the result depends on the domain $Omega$? Is there a big difference between a compact and an open domain? Does the regularity of the boundary $partial Omega$ play any role?



    I'd also appreciate if you have a good reference to this kind of result so that I can read further into this interesting issue. Happy New Year to all of you.










    share|cite|improve this question



























      7












      7








      7


      1





      Let $Omega subset Bbb R^n$. For a diffeomorphism (or merely a differentiable bijection) $varphi:Omega to varphi(Omega)$, we have the formula
      $$
      int_{Omega} fcircvarphi^{-1}(x), dx = int_{varphi^{-1}(Omega)} f(y)|Dvarphi(y)| ,dy.
      $$




      How much can we generalize the class in which $varphi$ is allowed to lie in? Is it enough that we have, says, a bijection $varphiin W_{text{loc}}^{1,infty}(Omega ;Bbb R^n)$ or even $varphiin W_{text{loc}}^{1,1}(Omega ;Bbb R^n)$?




      How much does the result depends on the domain $Omega$? Is there a big difference between a compact and an open domain? Does the regularity of the boundary $partial Omega$ play any role?



      I'd also appreciate if you have a good reference to this kind of result so that I can read further into this interesting issue. Happy New Year to all of you.










      share|cite|improve this question















      Let $Omega subset Bbb R^n$. For a diffeomorphism (or merely a differentiable bijection) $varphi:Omega to varphi(Omega)$, we have the formula
      $$
      int_{Omega} fcircvarphi^{-1}(x), dx = int_{varphi^{-1}(Omega)} f(y)|Dvarphi(y)| ,dy.
      $$




      How much can we generalize the class in which $varphi$ is allowed to lie in? Is it enough that we have, says, a bijection $varphiin W_{text{loc}}^{1,infty}(Omega ;Bbb R^n)$ or even $varphiin W_{text{loc}}^{1,1}(Omega ;Bbb R^n)$?




      How much does the result depends on the domain $Omega$? Is there a big difference between a compact and an open domain? Does the regularity of the boundary $partial Omega$ play any role?



      I'd also appreciate if you have a good reference to this kind of result so that I can read further into this interesting issue. Happy New Year to all of you.







      real-analysis measure-theory differential-geometry reference-request pde






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited yesterday

























      asked yesterday









      BigbearZzz

      7,32621648




      7,32621648






















          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%2f3060597%2fchange-of-variable-formula-for-a-non-differentiable-mapping%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.





          Some of your past answers have not been well-received, and you're in danger of being blocked from answering.


          Please pay close attention to the following guidance:


          • 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.


          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%2f3060597%2fchange-of-variable-formula-for-a-non-differentiable-mapping%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

          An IMO inspired problem

          Management

          Investment