$mu$, a Borel measure on $mathbb{R}$ satisfies $mu(K)<infty$ for compact K, $mu(x+E)=mu(E)$. Then $mu(E)...












1














I wish to show that any Borel measure which is finite over compact sets and is invariant under Euclidean isometrics, is in fact Lebesgue's measure multiplied by a positive factor. In other words: $forall E in mathcal{B_{mathbb{R}}} : mu(E) = ccdot lambda(E)$, when $lambda$ is Lebesgue's measure.



I proved that for $c = mu ([0,1])$ and for any open set in $mathbb{R}$. Now defining $mathcal{E} = {E : mu(E) = mu([0,1])cdot lambda(E) }$ I wish to demonstrate that $mathcal{E}$ is a $sigma$ algebra and then $mathcal{B}_{mathbb{R}}subseteqmathcal{E}$.



I don't succeed to show closure under complement, and I would like some help with that.



For non-emptiness and closure under countable unions:





  • $mathcal{E}$ is not empty , because it contains all open sets.


  • ${E_n}_1^infty$ a disjoint collection in $mathcal{E}$ : $mu(biguplus E_n) = sum_1^inftymu(E_n)=sum_1^infty mu([0,1])cdot lambda(E_n) = mu([0,1])cdot lambda(biguplus E_n)$. Thus $mathcal{E}$ is closed to countable unions (I am using here a lemma which promises it's enough to demonstrate it for disjoint collection).










share|cite|improve this question





























    1














    I wish to show that any Borel measure which is finite over compact sets and is invariant under Euclidean isometrics, is in fact Lebesgue's measure multiplied by a positive factor. In other words: $forall E in mathcal{B_{mathbb{R}}} : mu(E) = ccdot lambda(E)$, when $lambda$ is Lebesgue's measure.



    I proved that for $c = mu ([0,1])$ and for any open set in $mathbb{R}$. Now defining $mathcal{E} = {E : mu(E) = mu([0,1])cdot lambda(E) }$ I wish to demonstrate that $mathcal{E}$ is a $sigma$ algebra and then $mathcal{B}_{mathbb{R}}subseteqmathcal{E}$.



    I don't succeed to show closure under complement, and I would like some help with that.



    For non-emptiness and closure under countable unions:





    • $mathcal{E}$ is not empty , because it contains all open sets.


    • ${E_n}_1^infty$ a disjoint collection in $mathcal{E}$ : $mu(biguplus E_n) = sum_1^inftymu(E_n)=sum_1^infty mu([0,1])cdot lambda(E_n) = mu([0,1])cdot lambda(biguplus E_n)$. Thus $mathcal{E}$ is closed to countable unions (I am using here a lemma which promises it's enough to demonstrate it for disjoint collection).










    share|cite|improve this question



























      1












      1








      1







      I wish to show that any Borel measure which is finite over compact sets and is invariant under Euclidean isometrics, is in fact Lebesgue's measure multiplied by a positive factor. In other words: $forall E in mathcal{B_{mathbb{R}}} : mu(E) = ccdot lambda(E)$, when $lambda$ is Lebesgue's measure.



      I proved that for $c = mu ([0,1])$ and for any open set in $mathbb{R}$. Now defining $mathcal{E} = {E : mu(E) = mu([0,1])cdot lambda(E) }$ I wish to demonstrate that $mathcal{E}$ is a $sigma$ algebra and then $mathcal{B}_{mathbb{R}}subseteqmathcal{E}$.



      I don't succeed to show closure under complement, and I would like some help with that.



      For non-emptiness and closure under countable unions:





      • $mathcal{E}$ is not empty , because it contains all open sets.


      • ${E_n}_1^infty$ a disjoint collection in $mathcal{E}$ : $mu(biguplus E_n) = sum_1^inftymu(E_n)=sum_1^infty mu([0,1])cdot lambda(E_n) = mu([0,1])cdot lambda(biguplus E_n)$. Thus $mathcal{E}$ is closed to countable unions (I am using here a lemma which promises it's enough to demonstrate it for disjoint collection).










      share|cite|improve this question















      I wish to show that any Borel measure which is finite over compact sets and is invariant under Euclidean isometrics, is in fact Lebesgue's measure multiplied by a positive factor. In other words: $forall E in mathcal{B_{mathbb{R}}} : mu(E) = ccdot lambda(E)$, when $lambda$ is Lebesgue's measure.



      I proved that for $c = mu ([0,1])$ and for any open set in $mathbb{R}$. Now defining $mathcal{E} = {E : mu(E) = mu([0,1])cdot lambda(E) }$ I wish to demonstrate that $mathcal{E}$ is a $sigma$ algebra and then $mathcal{B}_{mathbb{R}}subseteqmathcal{E}$.



      I don't succeed to show closure under complement, and I would like some help with that.



      For non-emptiness and closure under countable unions:





      • $mathcal{E}$ is not empty , because it contains all open sets.


      • ${E_n}_1^infty$ a disjoint collection in $mathcal{E}$ : $mu(biguplus E_n) = sum_1^inftymu(E_n)=sum_1^infty mu([0,1])cdot lambda(E_n) = mu([0,1])cdot lambda(biguplus E_n)$. Thus $mathcal{E}$ is closed to countable unions (I am using here a lemma which promises it's enough to demonstrate it for disjoint collection).







      measure-theory lebesgue-measure






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Nov 18 at 17:24

























      asked Nov 18 at 16:42









      dan

      470312




      470312



























          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%2f3003768%2fmu-a-borel-measure-on-mathbbr-satisfies-muk-infty-for-compact-k%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown






























          active

          oldest

          votes













          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%2f3003768%2fmu-a-borel-measure-on-mathbbr-satisfies-muk-infty-for-compact-k%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

          AnyDesk - Fatal Program Failure

          How to calibrate 16:9 built-in touch-screen to a 4:3 resolution?

          QoS: MAC-Priority for clients behind a repeater