Lebesgue outer measure regularity












0












$begingroup$


In $mathbb{R}$, the outer regularity of Lebesgue measure gives $m^*(A)=inf{m(A)mid E text{ is open and } A subset E}$.



Can we replace $E$ as measurable sets instead of open sets? I am not able to prove it. Looking for some hints. Thanks in advance.










share|cite|improve this question











$endgroup$

















    0












    $begingroup$


    In $mathbb{R}$, the outer regularity of Lebesgue measure gives $m^*(A)=inf{m(A)mid E text{ is open and } A subset E}$.



    Can we replace $E$ as measurable sets instead of open sets? I am not able to prove it. Looking for some hints. Thanks in advance.










    share|cite|improve this question











    $endgroup$















      0












      0








      0





      $begingroup$


      In $mathbb{R}$, the outer regularity of Lebesgue measure gives $m^*(A)=inf{m(A)mid E text{ is open and } A subset E}$.



      Can we replace $E$ as measurable sets instead of open sets? I am not able to prove it. Looking for some hints. Thanks in advance.










      share|cite|improve this question











      $endgroup$




      In $mathbb{R}$, the outer regularity of Lebesgue measure gives $m^*(A)=inf{m(A)mid E text{ is open and } A subset E}$.



      Can we replace $E$ as measurable sets instead of open sets? I am not able to prove it. Looking for some hints. Thanks in advance.







      measure-theory lebesgue-measure outer-measure






      share|cite|improve this question















      share|cite|improve this question













      share|cite|improve this question




      share|cite|improve this question








      edited Jan 10 at 16:22









      amWhy

      1




      1










      asked Jan 31 '17 at 15:10









      ArindamArindam

      338213




      338213






















          1 Answer
          1






          active

          oldest

          votes


















          3












          $begingroup$

          You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
          $$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
          This follows because the left infimum has a greater range.
          By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.



          Therefore, we have
          $$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$






          share|cite|improve this answer











          $endgroup$













            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%2f2122575%2flebesgue-outer-measure-regularity%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









            3












            $begingroup$

            You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
            $$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
            This follows because the left infimum has a greater range.
            By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.



            Therefore, we have
            $$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$






            share|cite|improve this answer











            $endgroup$


















              3












              $begingroup$

              You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
              $$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
              This follows because the left infimum has a greater range.
              By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.



              Therefore, we have
              $$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$






              share|cite|improve this answer











              $endgroup$
















                3












                3








                3





                $begingroup$

                You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
                $$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
                This follows because the left infimum has a greater range.
                By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.



                Therefore, we have
                $$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$






                share|cite|improve this answer











                $endgroup$



                You can but the result is somewhat trivial. Since every open set is Lebesgue measurable, we have
                $$inf{m(E)mid E text{ is measurable},; A subseteq E} leq inf{m(E)mid E text{ is open}, ;Asubseteq E} = m^*(A).$$
                This follows because the left infimum has a greater range.
                By monotonicity, $m^{*}(A) leq m^{*}(E) = m(E)$ holds for all measurable $E$.



                Therefore, we have
                $$m^*(A) leq inf{m(E)mid E text{ is measurable}, A subseteq E}$$







                share|cite|improve this answer














                share|cite|improve this answer



                share|cite|improve this answer








                edited Jan 10 at 16:06









                amWhy

                1




                1










                answered Jan 31 '17 at 15:14









                Henricus V.Henricus V.

                15.1k22048




                15.1k22048






























                    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%2f2122575%2flebesgue-outer-measure-regularity%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

                    'app-layout' is not a known element: how to share Component with different Modules

                    android studio warns about leanback feature tag usage required on manifest while using Unity exported app?

                    WPF add header to Image with URL pettitions [duplicate]